Price List ho. 50, Vols. II and III. ( Physical Apparatus. VOL. II. Apparatus and Supplies for general use. Introduction to Physics. Mechanics. Wave Theory. Acoustics. Optics. Heat. Meteorology. Cosmology. Electrically driven Whirling Table with double Gearing. MAX KOHL A. G CHEMNITZ (GERMANY) Adorfer Strasse 20. Telegraphic Address: Physik. ABC- Code 5* Ed. used. Fully paid-up Share Capital: £ 80,000. 50, II III e. All imitation or reproduction of Block strictly prohibited. 01.6224. Printed by Hugo Wilisch, Chemnitz. Preface. m The present list forms the second portion of our Price List No. 50 published in the autumn of 1909. The list here presented contains descriptions and prices of Physical Apparatus brought up to date in accordance with the present state of instruction in Physics. We have spared neither cost nor trouble to render the arrangement of the list as comprehensive as possible and to facilitate the selection of apparatus by means of suitable illustrations. The latter are reproduced from photographs almost without exception and therefore give an exact idea of the apparatus, as in making illustrations from drawings a certain amount of discretion is generally left to the draughtsman. A carefully compiled index at the end of the list facilitates the selection of apparatus. In presenting this Price List to physicists and others interested, we would ask that frequent use might be made of it and that the list itself might be kept for reference. It is always our endeavour to improve upon our apparatus and to make a thorough test of all goods before despatch, with a view to giving complete satisfaction to our customers. The steady increase in the output of our apparatus is proof that we are working in the right direction. In order to fill orders as rapidly as possible we hold a large stock of Physical Apparatus to the value of £ 20000 — £25000, while the completeness and modern character of the equipment of our works renders it possible for us to execute even the largest orders in the minimum of time. In order to shew the development of our 'works we append the following table shewing some of the important points in its progress: Year Area Working Space Available Power Number of Officials Number of Workmen Total Staff 1888 sq. m. 195 H. P. 3 16 19 1892 — 400 3 5 29 34 1896 1600 1750 13 11 68 79 1900 7000 7000 75 27 148 175 1905 10000 7000 150 35 270 305 1911 10600 10000 260 45 360 405 We shall be glad to send a complete description of our factory and its equipment, in the form of a pamphlet richly illustrated, gratis and post free to our clients. 239197 IV Conditions of Sale. Conditions of Sale. The prices in this list are for nett cash payment without discount. In liic case of Educational Institutions, time will be granted for-payment where orders re- presenting large sums are concerned, should this be necessary. The prices given are for delivery and payment at Chemnitz. In the case of deliveries not on account of German officials or German State or Municipal Educational Institutions, we reserve to ourselves the right to request the value of the account before despatching the goods or to require payment on delivery, unless we are convinced from previous dealings, or by obtaining references, as to solvency of customers. stamp Duties, payable in certain countries on accounts, should be met by the buyer. We neither concern ourselves with stamping nor assume any responsibility for any omission in this respect. Time of delivery is given where possible and is strictly adhered to, though we can take no responsibility for the consequences of unavoidable delays. In the case of foreign orders it is necessary to send us any special instructions as to con- signment or the payment of Customs Duly. Cases and packing are in all cases charged for separately at cost price. The prices ((noted for packing in the case of the individual articles only apply to simple packing for land transit; packing suitable for marine transit being as a rule charged double. We pack oversea consignments in zinc-lined cases or in cases with oil-cloth lining, unless otherwise requested. Oversea consignments to European Ports are sent in ordinary cases, unless marine packing is specially asked for. Packing is carried out with great care by skilled packers; but we protect our clients from loss by insuring consignments against breakage and loss, the lowest possible premium being charged. If damage is reported we therefore replace articles free of cost. Complaints are not considered unless made immediately on receipt of the goods. The illustrations appended to the Price List do not always agree perfectly in all particulars with the apparatus supplied, since in many cases alterations to and improvements in apparatus often shew themselves practicable. In the case of many of the illustrations, Auxiliary Apparatus, etc. are included in the illu- stration in order to facilitate the construction and use of the apparatus (e. g., Fig. 51,151, the experimental apparatus); these articles are not included in the price of the object, being supplied only when ordered separately. The scale of sizes given under the illustrations is intended to give a practical idea of the >i/.r of the apparatus, but is not binding as regards the exact size of the article. In the case of per>peetive drawings the scale usually applies to one dimension only. In connection with larger articles we have in many cases appended the nett and gross \\eights. Ml data as to weight are, however, only approximate and not binding. .Marine packing as a rule weighs about half as much again as packing for land transit. View of Factory. Awards. Chicago 1893. Gold Medal. Leipzig 1897. lANDINC'OFCOlUMBUS • Mncccxcii i WXjXCIIl- Chicago 1893. Administration Buildings, Mechanical Workshops and Cabinet Shops of Messrs Max Kohl A. G. Chemnitz. Gold Medal. International Exhibition. Paris 1900. GRAND-PRIZE LOVISIANA-PVRCHASE EXPOSITION. Grand Prix. St. Louis 1904. Cl. 4780, 4790, 4781,5664, 4785,4786,4787,4784. VI Awards. 3 Grands Prix. International Exhibition Brussels 1910. We have obtained the following awards at exhibitions: International Exhibition, Brussels, 1910. 3 Grands Prix. International Exhibition, St. Louis, 1904. ! ' Gold Medal. International Exhibition, Paris, 1900. Gold Medal. International Exhibition, Chicago, 1893. Two Prizes. Buenos Aires, 1910. Grand Prix. Allahabad (India), 1911. Gold Medal. Lemberg, 1907. Gold Medal. Rome, 1907. Large silver Medal. Liege, 1905. Two Grands Prix. Athens, 1904. Gold Medal Aussig, 1903. Gold Medal. Diisseldorf, 1898. Two Diplomas. Leipzig, 1897. Gold Medal. Gold Medal. St. Louis 1904. GOLD MEDAL LOVIS1ANA-PVRCHASE EXPOSITION. 2 Grands Prix. Liege 1905. Cl. 6589, 6590, 4783,4782, 4788.7489. Contents. VH Contents. vol. n. Page General hints III-XVT Preface Ill Conditions of sale IV Awards V, VI Contents VII Literature, together with abbreviations employed VIII Some testimonials as to physical apparatus and mechanical models IX— XIV Corrigenda for vol. I — III XV Apparatus and Supplies for General Use 201 — 250 Apparatus, Supplies and Materials for General Use 201 — 220 Measurement of lengths, angles, surfaces and volumes, Dividing Engines, Slide Eules 221—230 Balances and sets of weights 231 — 244 Measurement of time 244 — 250 Introduction to Physics 250 Mechanics (statics, dynamics and molecular effects) of solids, liquids and gases 251 — 411 Wave motions 411 — 417 Acoustics 418 — 464 Optics 465 — 566 Heat 567—649 Meteorology 650—660 Cosmology 660 — 662 vol. m. Magnetism 785—796 Static Electricity 797—838 Voltaic Electricity 839—949 Electro-magnetism and Electro-dynamics 949 — 1030 Electrical Oscillations. Wireless Telegraphy. Telephony. Selenium Cells. Thermoelectricity 1030—1064 Miscellanea 1064—1071 Appendix 1072 — 1074 Estimates of Cost for Physical apparatus 1075 — 1085 Estimates of Cost for Chemical supplies 1085 — -1093 Physical apparatus for projection 1094 — 1096 Alphabetical Name and Subject-matter Index 1097 — 1131 Equipments: see List 50, Vol. I. vm Literature, Abbreviations. Literature with List of Abbreviations. In compiling this Price List use was made in the first instance of the text-books and periodicals mentioned below -- both the older and newer editions of the text-books being considered. Where the edition is not expressly mentioned in the literature, the reference is to the edition mentioned below. As many apparatus are described in a number of text-books, preference is given in quoting the literature to the work giving the most complete ^details. Text-books and journals mentioned here and there are not included below. Abbreviations. Title. W. D. Leipzig 1905. Joh. Ambr. Earth the 3rd ed. are enclosed in square W. V. d. E. M. P. Chwolson, Lehrb. F r i c k, Phys. T. M. T. Gr i m s e h 1. Hofler-Poske. Kolbe, El.-L. Kolbe-Skellon. Gan.-Man. Gan.-Rein. W e i n h o 1 d, Physikalische Demonstrationen, 4. Auf 1. (friiher bei Quandt & Handel). The references to brackets. W e i n h o 1 d, Vorechule der Experimentalphysik, 2. Aufl. Leipzig 1874, Quandt & Handel. Miiller-Pouillet-Pfaundler, Lehrbuch der Physik und Meteorologie, 10. Aufl. 1906—1909, Bd. I, II1, II1, III, IV1. Braunschweig, Friedr. Vieweg & Sohn. Chwolson, 0. D., Lehrbuch der Physik, Bd. I— IV, Braunschweig 1902—1908. Friedr. Vieweg & Sohn. Dr. J. F r i c k s, Physikalische Technik von Dr. 0. Lehman n, 7. Aufl. 1904 — 1909. The references to the 6* ed. are enclosed in square brackets. Friedr. C. G. M ii 1 1 e r, Technik des physikalischen Unterrichts nebst Einfuhrung in die Chemie. Otto S a 1 1 e, Berlin 1906. Tyndall, Der Schall, deutsch von H. Helmholtz und C. Wiedemann. Braun- schweig 1874. Friedr. Vieweg & Sohn. Tyndall, Die Warme, deutsch von A. v. Helmholtz und C. Wiedemann, nach der 8. Auflage des Originals, Braunschweig 1894. Friedr. Vieweg & Sohn. Tyndall, Das Licht, deutsch von C. Wiedemann, 2. Aufl. 1895. Braunschweig. Friedr. Vieweg & Sohn. Helmholtz, Die Lehre von den Tonempfindungen, 4. Aufl. 1844. Braunschweig. Friedr. Vieweg & Sohn. E. Grimsehl, Lehrbuch der Physik, Leipzig 1909. P o s k e, Dr. P., Oberstufe der Naturlehre. Nach A. Hoflers Naturlehre fur die oberen Klassen der osterreichischen Mittelschulen fur hohere Lehranstalten des Deutschen Reichs bearheitet. Braunschweig 1907. Friedr. Vieweg & Sohn. H 6 f 1 e r, Physik mit Zusatzen aus der angewandten Mathematik, aus der Logik und Psy- chologie und mit 230 Leitaufgaben. Braunschweig 1904. Friedr. Vieweg & Sohn. B. Kolbe, Einfuhrung in die Elektrizitatslehre, 1. Aufl. 1893 u. 1895, 2. Aufl. 1904 n. 1905, Berlin, Jul. Springer. Introduction to Electricity; Kegan, Paul, Trench, Trubner & Co., Ltd. London 1908. Ganot-Maneuvrier, Traite elementaire de physique, 23. Aufl. Paris 1905. Librairie Hachette et Cie. Ganot-Atkinson- Reinold, Elementary Treatise on Physics experimental and applied; London und Bombay 1906. Longmans, Green & Co. ineuvrier-Brito, Tratado elemental de Fisica. Paris 1885. Librerfa B o u r e t und Libreria de Hachette y Cia. W e i s k e, Lehrbuch der Physik und Meteorologie. Leipzig 1858. Loop. Kleiber, Lehrb. f. Gymnas. 3. Aufl. Miinchen G a n o t - M i de Ch. G a n o t - Dr. V o s s. Kleiber, Joh., Lehrbuch der Physik fur humanistische Gymnasien. und Berlin. 1904. Kleiber, Joh., Physik fur die Oberstufe. Miinchen und Berlin 1905. R. Oldenbourg. Kleiber und Scheffler, Elementar-Physik mit Chemie fur die Dnterstufe, 4. Aufl., Miinchen und Berlin 1908. R. Oldenbourg. Meyer, K., Naturlehre (Physik und Chemie) fur hohere Madchenschulen, Lehrerinnen- Seminare und Mittelschulen. 4. Aufl. Leipzig 1906. Rosenberg, Dr. Karl, Experimentierbuch fur den Unterricht in der Naturlehre. 2. Aufl. Wien und Leipzig 1908. Alfred Holder. Wiedemann und E b e r t, Physikaliscb.es Praktikum, 4. Aufl. 1899. Braunschweig. Friedr. Vieweg & Sohn. H a h n, Herm., Handbuch fur physikalische Schiilerubungen. Berlin 1909. Julius Springer. Kaiser, W., Physikalische Schiilerubungen. Leipzig 1908. Ztechr. f. d.phys. u.chem.U. Zeitschrift fur den physikalischen und chemischen Unterricht. Jul. Springer, Berlin. Poggendorfs Annalen der Physik und Chemie. Wiedemanns Annalen der Physik und Chemie. Drudes Annalen der Physik Comptes rendues hebdomadaires des seances de 1'acaderaie des sciences. Zeitschrift des Vereins deutscher Ingenieure, Berlin. W. u. E., phys. Prakt. Pogg. Ann. Wied. Ann. Drudes Ann. Compt. rend. Z. d. V. d. J. Quelle & Meyer. Herausgegeben von F. Poske. Testimonials. IX Some Testimonials as to Physical Apparatus. Trier, 13th April, 1911. 1 beg to express my warmest thanks for the protecting sheet for the Induction Apparatus as well as for the appa ratus subsequently supplied. These are very well con- structed and work faultlessly. Oberlehrer Reimann. Vegesack b. Bremen, 13th April, 1911. I beg to inform you that the consignment of appa- ratus for teaching purposes, which arrived a few days ago, has met with my entire satisfaction. Oberlehrer Dr. H. Kohlmann. Iterlin-Wilmersaorf, 14th April, 1911. I am very satisfied with the apparatus with which you have supplied me. They can lay claim to the highest precision and are characterised by thoroughness and neatness of construction, thus affording great pleasure to the eye. As a general rule these excellent qualities are wanting in apparatus made by other firms. And no one who has observed the steady perfection in construction of Kohl's apparatus during the last few years can say that the firm of Kohl has not endeavoured to establish firmly its old and renowned reputation. Dr. Lotzbeyer, Oberlehrer an der Oberrealschule nebst Reformrealgy mnasium . Gross- Lichterfelde, 14th April, 1911. You will also be glad to hear that nothing has gone astray or become broken amonvill gladly consider you in future orders. Prof. Hiiiimel, Seminar. X Testimonials. (Jlarisegg bei Steckborn, 9th February. 1911. Finally, I must thank you for the good construction ol i lie apparatus. Dr. Max OettL, Schweizerisches Landerziehungsheim. C u x h a v e n, 1st February, 1911. We shall require additional apparatus this year and I have no doubt that your esteemed firm will obtain the order as the goods supplied by you have been found faultless. V. Worch. Offenbach a./M., 24th January, 1911. I must not fail to inform you that the apparatus and equipment supplied to our School last summer satisfy all conditions required of them; especially is this the case for the Projection Apparatus and Switchboard, with which I am very satisfied. Oberlehrer Richter, hohere Madchenschule. Campobasso, Italy, 19th January, 1911. I have become acquainted with the good qualities of apparatus constructed in your workshops in the Physical Institute of the Royal University of Cattania (Sicily) where I acted as Assistant up to last year, and I desire to obtain apparatus of your construction. Prof. C. Bellia, R. Liceo-Ginnasio ,,Mario Pagano". Montreal, 16th December, 1910. The cases last received from you have been opened and I must inform you that I am perfectly satisfied with their contents. The packing is perfect, etc. ficole des Hautes Etudes Commerciales de Montreal. B o z e n, 16th December, 1910. I would remark, in conclusion, that we are perfectly satisfied with the consignment received three years ago. Convent vom Allerheiligst. Sacrament, Bozen, South Tyrol. Sarospatak (County Zemplen), Hungary, 14th December, 1910. We are very satisfied with the Physical Apparatus ordered from you this year. Alexander Mailer. Obergymn.-Lehrer. \V i 1 m e r s d o r f, 9th December, 1910. The quality and practical arrangement of the goods supplied arc in perfect accord with our wishes. Dr. Meyer, Oberlehrer an ilcr Cecilienschule. Go Id a p, 6th December, 1910. The apparatus supplied have arrived without fault and work well. Oberlehrer Franz Busch, Kgl. Realgymnasium. Los Angeles, Cal., 22nd November, 1910. Through local agents we are receiving now a number of pieces of apparatus of your make. We are highly pleased with these. Manual Arts High School, Geo. E. Mitchell, Science Dc|.t. Lucca, 17th November, 1910. The Andrew Press has arrived in good condition and works very well. R. Liceo. Glogau, 17th November, 1910. Many thanks for sending Price List No. 21 with supple- ments and for the excellence of construction of the goods to our recent order, etc. Oberlehrer G. Koch, hohere Madchenselmle. Philadelphia, 12th November, 1910. Referring to our order Mounted Chromatic Forks ordered of us by the John Hopkins University, Dr. John B. Watson would take this occasion to express Dr. Watson's appreciation of your manner of filling this order and to state that other orders for apparatus will be placed by Dr. Watson in the near future. Arthur H. Thomas Company. Rochlitz, 4th November, 1910. The consignment has met with my complete sat is - I'iiction and I beg to thank you for it. Rich. Miiller, Seminaroberlehrer. Davos Platz, 3rd November, 1910. I am very pleased with the Coil supplied on 5th Fe- bruary, 1909, as the efficiency is nearly the same as ilie modern apparatus without interrupter; and I hope that the Induction Coil ordered may turn out as good. A. Rzewuski. I) j u r s h o 1 in, Sweden, Ist November, 1910. Since it is only during the last few days that we have been able to deal with our new school buildings we have only now been able to unpack the Physical Apparatus supplied by you. We have found everything very t-atis- factory and we have great pleasure in giving you this testimonial. Djursholms Samskola. Testimonials. XI Kecskemet i, 27th October, 1910. Theodolite arrived in perfect condition. Am very satisfied with it. Dir. Racsch, P. D., Oberrealschule. St. G alien, 21st October. 1910. I have great pleasure in repeating to-day my high appreciation of the numerous apparatus supplied last winter for the St. Gallen Industrial and Realschule. Real- und Gewerbeschullehrer H. Schmid. Vilna, 3rd October, 1910. I beg herewith to express my thanks at the correct construction of my first order from you. 1 received both consignments in good condition. Mannliches Gymnasium Pesotsky. Szaezvaros, Hungary, 8th September, 1910. We are eminently satisfied with the articles and the work. Franz Simon, Gymnasirldirektor. K i e f f, 3rd September, 1910. It is with pleasure that we inform you that the client is very satisfied with the goods supplied and we take this opportunity of expressing our most sincere thanks for the careful manner in which this order Has been executed. Olszevitz and Kern. Berlin, 16th August, 1910. We beg to inform you that we have received the goods and are extremely satisfied with the manner of coastruction. Mechanics Laboratory oJ the Royal Mining .Academy, Schmidt, Assistant. (Translation.^ Ufa, 14th August, 1910. On opening the cases all the pieces of apparatus were found to be in perfect condition, and I beg to express my best thanks for the same. Mannliches Gymnasium, Ufa. P f i b a m, 29th July, 1910. I feel it my duty to express my most sincere thanks for the apparatus supplied during the school year 1908/9 through Messrs. J. & J. Iric, Prague, for our Electroteclmical Collection. The working of all apparatus is perfect. Ing. W. Kazel. G o r 1 i t z, 21st July, 1910. Everything with which you have supplied us is con- structed in the best possible manner. Dr. Graetzer. A q u i 1 a, Italy, 15th June, 1910. I must inform you that everything has been received in good condition and that I am perfectly satisfied with the fine and accurate construction of the apparatus supplied to our Institute. Ottaviano Loiif.o, Professor of Physics. P. erlin-Wilmersdorf, 11th May, 1910. The apparatus supplied are to my entire satisfaction. Oberlehrer Dr. Lotzbeyer, Oberrealschule. Pol?, 8th May, 1910. I am also perfectly satisfied with the two pieces of apparatus last supplied. Ginnasio reale Prof. A. Gregoretti. E s k t e r g o n n, 3rd April, 1910. During the last four to five years in which I have had dealings with you, partly through Messrs. Calderoni & Company, I have been able to convince myself of the soundness and excellence of your firm. Molakovszky Laszlo, Bottyan Janos u. 11. Astrachan, 1st April, 1910. We have received the apparatus supplied. All the apparatus has arrived safely and is of excellent quality, for which we thank you. Realschule. St. Gallen, 28th March, 1910. The large consignment of Physical Apparatus intended for the St. Gallen Industrial School, which are specially intended for teaching Electricity, has arrived in good con- dition. All apparatus work faultlessly and their sound and exact construction eminently satisfactory. The appa- ratus are a real ornament to the instructional collection of the Municipal Industrial School. H. Schmid, Reallehrer. Holzmindeu, 26th March, 1910. It givjss me great pleasure to inform you that I am very pleased with the precise manner in which our order has been executed. Th. Lehmann, Oberlehrer, Landschulheim. Jaroslav, 23rd March, 1910. The apparatus supplied in January last were all in order and work well. We thank you for same. Lehrer-Institut. Prague, 10th March, 1910. The Monochord is very nicely constructed and is in accordance with my wishes. Mathematico-Physical Institute oJ the German University. XII Testimonials. A u b u r n, Ala., 5th March, 1910. The lot of apparatus which I ordered in November was received a few days ago and is entirely satisfactory in every way. I wish to thank you for your efficient and prompt execution of my order in every detail. Alabama Polytechnic Institute, Dept. of Physics. Essen (Ruhr), 22nd February, 1910. I acknowledge receipt of your consignment of 19th ult. and after testing the apparatus beg to express my satis- faction with the goods. Prof. Mathee, Direktor der Kgl. Maschinenbauschule. K o m o t a u, 19th February, 1910. I am again very satisfied with the reliable and sub- stantial construction of the apparatus. Prof. Dr. Franz Wolden, K. K. Staats-Gymnasium. Hartford, Conn., 12th February, 1910. The apparatus you shipped to me arrived some time ago and is entirely satisfactory. Trinity College, Jarois Physical Lab. Ley sin, Canton de Vaud, 12th February, 1910. The apparatus for studying Radioactivity are espe- cially characterised by their construction, and the mixture of Radium and Zinc Sulphite is excellent from the phos- phorescence point of view, for which I am very much obliged to Messrs. Max Kohl. W. Stefko, Moscow. P a b i a n i c e, 1st February, 1910. All articles received in good condition and undamaged. Directors of the Commercial Academy. Bruck a. d. Mur, 27th January, 1910. I am very pleased with the consignment just received. Dr. Paul Gaulhoser, Physikalisches Kabinett der K, K. Staatsrealschule. Hernosand, 27th January, 1910. I am very pleased with the apparatus supplied. E. Tham, Technische Elementarschule. Salzburg, 25th January, 1910. Many thanks for the goods with which, as in previous instances. I am very satisfied. Karl Schnizer, Teacher ;it the Public Commercial School. Sarospatek, 24th January, 1910. The Physical Apparatus ordered have arrived and the packing is perfect. I am very well satisfied with the get- up of the- articles. Alex. Mailer, Teacher of Physics, Obergymnasium. P o z s o n y, 10th January, 1910. The instruments have evoked all-round approval and are faultless in every particular. Mather Oszwald & Tarsa. Leipzig, 3rd January, 1910. At the commencement of the present ye?r I obtained from you for the new Schiller- Realgymnasium here a double- crank Rheostat after Briisch for a D. C. supply of 220 volts. I am very pleased with the apparatus. Professor Dr. Starke, Oberlehrer am Schiller-Realgymnasium. Droyssig b. Zeitz, 27th December, 1909. The apparatus which your firm has supplied are to my entire satisfaction; they work very well. Seminarlehrer Jantzsch. Etteaheim, 22nd December, 1909. The transformer works well and economically when connected up as stated. J. Ziegler, Prof, am Realgymnasium. Riga, 19th December, 1909. The last consignment duly to hand io good condition. The precise and substantial manner of construction of the apparatus leaves nothing to be desired. The apparatus which you supplied a year ago also have been found ex- cellent for teaching purposes. C. Krause, Hohere Tochterschule von 0. v. Hasford. Hermannstadt, 15th December, 1909. The consignment for the Realschule received yesterday. The apparatus are constructed in the excellent manner generally reputed to your firm and we are very pleased with them. Direktion d. ev. Gymnasium A. B. (sd.) C. Albrlch. C z e r n o w i t z, 25th November, 1909. 1 wish before all to emphasize the fact that every piece of apparatus is nicely and accurately constructed and that tests have shewn the same to work faultlessly. I therefore consider it my duty to express to you in the name of the Institution for which I work many thanks for the care and precision with which you have filled this order. Professor Alexander Buga, Kustos d. physksl. Kabinetts am III. Staatsgymnasiurn. Tar now. i_'r' November, The Physical Apparatus supplied to our Gymnasium by your esteemed house have been received and we are perfectly satisfied \vitli the eonstruelinn of the i-ame. I. Staatsgymnasiurn, Physikalisches Kabinett. Testimonials. xni W o 1 o g d a, 9th October, 1909. The Physical Apparatus supplied by you to my order been received in good condition and well packed, and have been found to justify themselves in use, for which please accept my best thanks. II. Weibl. Gymnasium. Rotterdam, 24th October, 1909. I have obtained from you for my School (II. Hohere Knabenschule) apparatus to the value of £ 100. The entire consignment I find to be perfectly satisfactory. Dr. D. de Lange. Leobschutz, The apparatus are excellent. 23rd October, 1909. Egl. Seminar. T i f 1 i s, 1 1th October, 1909, I beg to express my thanks for the faultless and accurate manner in which the apparatus are constructed. Commercial Academy. G e b w e i 1 e r, 2f>th September, 1909. We must say that taking everything into consideration we are very pleased with the objects supplied. In par- ticular the nice lecture table and the electrical plant have given us great pleasure, while the Projection Apparatus fulfils all demanas that can be placed on a cheap instrument. Dr. Weill, Gymnasium. Bologna, 17th September, 1909. We are quite satisfied with the Pump supplied. Societa Italiana Fabbriche Lampade Phoebus. II e r m a n n s t a d t, 8th September, 1909. I received your consignment a week ago and thank you for prompt despatch. It is quite a festival to me when I receive new apparatus from you of your wonderful con- struction. Everything has arrived in good condition. Direktor C. Albrich junior, Evang. Gymnasium A. B. Utrecht, 23rd July, 1909. It gives me great pleasure to inform you that the in- struments manufactured by you, supplied to the Ludgers Teachers Seminary, Hilversum, have met with the entire satisfaction of the users. Thanking you for the con- signment, etc. FT. Andreas, St. Gregoriushuis. G r a z, 10th July, 1909. I was very pleased with the apparatus (Spark Coil, Tcsla Apparatus, etc.) supplied to the Marine Institute. E. Weber, K. K. Professor. W o t k i n s k, 6th July, 1909. Kindly accept my best thanks for filling in such a complete manner my order for Physical Apparatus which you supplied last year for the Physics Dept. of the Technical School, Votkinsk. Direktion der mittleren technischen Schule. R a t i b o r, 26th June, 1909. I beg to inform you that I am pleased with the Air Pump as with all apparatus supplied by you. Oberlehrer Langner, Realgymnasium. Villingen, 25th June, 1909. In conclusion. I feel compelled to express my best thanks for the careful manner in which you have filled the order and — so far as I have been able to test — for the substantial and tasty manner in which the individual pieces of apparatus have been constructed. Prof. E. Hensel, Realgymnasium . 0 r s c h a, Gouv. Mohileff, 30th May, 1909. I now find time to express my best thanks, for all apparatus have been received in excellent condition. M. Vastschinski, Teacher of Mathematics at the Girls' Gymnasium. V a lie jo, Cal., 14th May, 1909. The goods arrived in fine condition. They were re- markably well made, and each piece of apparatus works to perfection. I congratulate you upon 'the possession of such skilled workmen. Carl H. Nielsen, Principal, Vallejo High School. 0 dense, 11th May, 1909. I beg herewith to confirm that the apparatus ordered have been received in good condition and to express to you my best thanks for same. Technische Schule. Wilmersdorf-Berlin, 1st May, 1911. The entire equipment of the class rooms and museums for Physics and Chemistry at the Cecilienschule, and the equipment of the Chemical Laboratory, have met with entire approval. Everything is constructed in a very practical manner and .of faultless material and works with ease and certainty. The apparatus of our collection also, which almost without exception came from your factory, have shewn themselves in vise to be thoroughly well and precisely constructed, work well, and are thoroughly sub- stantial. Dietrich Meyer, Ordinary Teacher at the Cecilienschule. Steglitz, near Berlin, 5th May, 1911. During the last three years you have supplied the internal equipment of our five Physics rooms, and supplied the greatest part of our apparatus for demonstrations and students' use. It is with pleasure that I inform you that we are quite pleased with everything and that we all of us — teachers and students — like to work with your goods since they are reliable and always nice in appearance. Oberlehrer C. Roebling, Paulsen-Realgymnasium. XIV Testimonials. Some Testimonials as to Mechanical Models after Prof. Eugen Meyer, Charlottenburg. Royal Technical High School. Hanover, 23rd April, 1910. In reply to your enquiry, I beg to say that from pre- vious experience I am perfectly satisfied with the cons- truction and action of the Models after Prof. Meyer. Prof. Dr. Ing. Michel. Royal Mining Academy. Berlin, 7th April, 1910. In reply to your enquiry of 5th April, I have to say that I am quite satisfied with the Meyer Models sent. Prof. Dr. E. Jahnke. Direction of the Technical State Institutions. Chemnitz, 10th May, 1910. In reply to your favour of 5th April, 1910, I have to inform you that the Models designed by Prof. Eugen Meyer and supplied by you for instruction in Technical Mechanics, intended for the Mechanics and Electrotechnical Depart- ments of the Academy of Crafts and for the School of Mechanics, and for instruction in Building in the Archi- tectural Department of the Academy of Crafts, have been found satisfactory. Die Direktion der Technischen Staatslehranstalten. Miihlmann. Direktion des Thiiringischen Technikums. 1 1 m e n a u, 28th April, 1910. The construction of the model is very well thought out and is very rigid in spite of the numerous movable sections. The use of this model greatly facilitates demons- trations so that it can be employed with advantage for teaching purposes. Direktion des Thuring. Technikums Ilmenau. Prof. 0. Schmidt. Konigl. Sachs. Bauschule. Plauen i. V., 7th April, 1910. In regard to your enquiry of the 5th inst., we have pleasure in informing you that the Models Nos. 3 and 5 for technical Mechanics, after Prof. Dr. Meyer of Char- lottenburg, obtained from you, are considered as models very well adapted from their mode of construction and capability of demonstration for explaining the principles of Bending Phenomena. The Models mentioned can be warmly recommended to all technical schools. Die Direktion der Koniglichen Bauschule. Baurat Prof. Albert. The following institutions have already obtained from us Mechanical Models as suggested by Prof. Eugen Meyer, Charlottenburg: Staatliches Technikum, Konigliche Bergakademie, Technische Staatslehranstalten, Artillerie-Akademie Mechaniscb.es Laboratorium, Bergskolan, Konigl. Techn. Hochschule, Konigl. Sachs. Bauschule, Thuringisclics Technikum, Cniversity of Sydney, Technikum, T< rhimche Hochschule, Hamburg. Berlin. Chemnitz. St. Petersburg. Falun (Sweden). Hanover. Plauen (Vogtl.). Ilmenau (Thur. ). Sydney. Winterthur. Danzig-Langfuhr. Technische Mittelschule Konigl. Preufiische hohere Schiffs- und Maschinenbauschule, Konigl. Fachschule, Konigl. Fachschule, Maschinen-Bauschule, Grossherzogliche Baugewerk- und Maschinenbauschule, Ingenieur- und Deckoffizierschule Militartechnische Akademie, Technische Hochschule, Eidgen. Polytechnikum, Berlin. Kiel. Schmalkalden. Leipzig. Barmen-Elberfeld. Varel. Wilhelmshaven. Charlottenburg. Braunschweig. Ziirich. Corrigenda. XV Corrigenda to Vol. I. Page 32, Fig. 50,199 B. A design is not registered. „ 120, No. 50,494. The Figure refers to No. 50,500, not 50,490. .. 121, No. 50.502. The voltage limits for one circuit are 03 — 110 and 160 volts respectively, not 0.03. 127, No. 50,534. This Sliding resistance is shown in fig. 50,534. .. 133, No. 50,565. The price of the Gas Generator does not include motor drive, ion Par 1 1 14o! line 6 The remarks re the switching out of the compound winding are not valid and should be deleted. .. 142, line 5 and 6J 144. last par. but one 1 The final remark g^ould read: ,,In this manner the given speed at full load can be in- creased by about 15% at full load." The speed cannot be decreased. 14(>. last par. but three J 186, No. 51,074. The reference to W. D. relates to the 3^ Edition [and the 2nd Edition], for the fourth [and third] editions the following hold: W. D. 323 [305]. 190 — 192. Physical Apparatus for Projection. Pages 190 — 192 no longer hold and should be replaced by pp. 1094—1096. .. 1221. Special optical outfit with Steinheil Group antiplanet. Read = 1 : 6,5, not 1 : 4,5. „ 1224, No. 9568. Biconcave lens costs £ 1. 0. 0, not £ 1. 5. 0. „ 1228, No. 9656. Projection screen with electric device and with tilting device costs £ 31.15.0, not £ 25. 10.0. Corrigenda to Vols. II and III. Page 218, No. 51,361. Carbon Capsule costs £ 0. 1. 6, not £ 0. 1. 0. ., 2>0, No. 51,413. Mohr's Burette with pinch cock, 100 ccm, costs 3 s. 6 d, not 4 S. 6 d. .. 236, Nos. 51,569 and 51,570. The load which this balance may carry is expressed in kg. ,, 259, No. 51,819. Engelmeyer's Kinegraph costs, constructed as stated, £ 5. 10. 0 and not £ 3. 0. 0. A simple pattern for demonstrating the parallelogram of forces can be obtained for £ 3. 0. 0. ,. 2(il. No. 51,830. 3 Balance Pans of 50 g each and 1 Set of Weights with one 100 g weight, two 50 g, and twelve 10 g, suitable for the apparatus, cost £ 0. 15. 0 extra. ,. 273. No. 51,904. 27 Double Hook Weights are supplied instead of 26. .. 279, No. 51,959. The large Whirling Table has a width of 32 cm, not 37 cm. .. 279, Nos. 51,951 — 51,958. 1 Whirling Tables. These numbers and prices no longer apply, being replaced by the •27!(. Xos. 51,961 — 51,968. / data given which is inserted between pp. 278 and 279. .. 337, Nos. 52,465 and 52,466. The Hydraulic Press is equipped with a safety-valve for 20 atm., not 25. ., 340, No. 52,485. The last note above Pellat's apparatus: "The piston is packed with mercury" is belonging to No. 52,483. „ 363, Pig. 52,589. This figure refers to No. 52 689, not 52,589. .. 404, No. 53,058. Air reaction wheel. The figure of Fr. phys. Techn. is read: 3689, and not 2689. .. 415. No. 53,171. The Wave Machine after Steindel is priced at £ 9.0.0 and not £ 6.0.0. .. 4:w. No. 53,417- Tuning Forks with Electromagnetic Drive. The words: "By reducing the size of the orifice" should only come in after "pitch". „ 488, No. 53,860. The addition to the optical disc gives only five cones of rays, not eight. .. 532, Fig. 53,385. Read 54,385, not 53,385. ,, 545, No. 54,529. The price of Classen's interference apparatus is to be understood without glass plates. The plates cost £ 1. 5. 0. „ 809, No. 60,261. Sheet Iron Cube, and not Tube, is intended. ',, 809, No. 60,266. 2 fixed Sounders, 2 solid and 2 hollow Spheres are supplied, not hollow cylinders. „ 860, Nos. 61,023 — 61,047. Thermopiles. "Hell's Dyaaphors" are no longer supplied. „ 865, Section 2. Leads and wires see vol. II, not vol. I. ,, 968, No. 62,400 e. Universal Stand after Kolbe The words "with two glass walk" should be deleted. ,, 980, Table. Induction Coils. The Figure No. 62,533 cited in type C applies only to the larger Induction Coils from size 8 upwards. The smaller coils have instead of the pachytrope a simple reversing switch tor double commutation. ,. 982, No. 62,666. The Wehnelt Interrupter now costs £ 3. 15. 0, and not £ 3. 10. 0. .. 1009, Fig. 62.078 H. Read 62.97811, not 62,078 H. ,. 1010, No. 50,521. The Series Resistance can be used for 2 — 25 amps., not 5 — 24 amps. No. 51 100—51 103. Apparatus, Supplies and Materials for General Use. Work Stand. 201 51 100 A. 1:10. 51100B. 1:9. Apparatus, Supplies and Materials for General Use. 51,100. Physical Work Stand (Edelmann's), Pigs. A and B, with case. Eegarding the em- ployment of the work stand, see F i g. 51.103. Price, exclusive of the auxiliary parts shown in Fig. 51,103 (see No. 51,103), of iron . . The stand consists of a tripod with pillar, 8 brass cross clamps which can be firmly clamped to the pillar, and some ebonite, glass, iron and brass rods on to which electrodes, terminals, supports, tongs and insulating handles may be screwed. The stand can be placed either vertically or horizon- tally, and is widely used in physical experiments, e. g., for setting up lenses and prisms and spectrum tubes and for experiments with Leyden jars, induction coils, etc. ."> 1 , 1 01. - - T h e preceding, of Brass, tripod of zinc .">!,! 02. --The preceding, of Brass, with half as many clamps, holders and accessories again as in foregoing £ s. d. 4. 0. 0 4. 10. 0 6. 0. 0 Auxiliary Parts for Edelmann Work Stand, in accordance with Fig. 51,103, p. 202 1. '2 (Jlass Tubes for impact pressure of water (>. 2. 6 Carbon Bods for demonstrating the electric arc ". 3. The stand, assembled as a Henley discharger serves for the ignition of gun-cotton <>. 4. Roget's Spiral and Bowl (>. .">. Reading Telescope (see also Fig. 51,103, No. 8) 1. 6. Glass Funnel with metal rod for igniting ether (>. 1. 1. 0. 6. 12. 2. 4. 7. Glass Vessel with 1 carbon plate, 1 zinc plate and 1 copper plate for making up a cell .... (). 8. Scale for galvanometer readings (Telescope, see No. 5), with holder 0. 8. 0 9. 4 Lenses, 2 diaphragms, 1 preparation holder for making up a Galilean, a terrestrial and an astro- nomical telescope as well as a microscope 1. 2. 0 10. Lamp, slit diaphragm, lens and prism for demonstrating the spectroscope (telescope, see No. 5) . 0. 10. 0 11. 2 Spectrum Tubes, with hydrogen and oxygen JO. 7. 0 13" 202 Apparatus,*" Supplies and Material for General Use. N.I. M 101 - 51100 and 51103. 1 : 9 and 1 : 14. 51.104. Universal Stand (Bunsen's), massive construction, on iron foot, Figure (W. D., £ »• d. Fig. 35. - - M. T., p. 10), with the single parts ISTos. 1 — 9 listed underneath . . . .11. 2. 0 1. Iron Stand (Is. 8d.); 2. 2 Clamps, 1 small, without double socket (2s. 6 d.); 3. Clamps, k 2, large, without double socket (3 S.); 4. Eetort Holder, d, without double socket (3s. 7 d.); 5. Double Sockets, m, 3 in number, together (6s.); 6. Eing, r 1, with socket, 7 cm diameter (Is. 3d.); 7. Eing, r 2, with socket, 10 cm diameter (Is. 5d.); 8. Eing, r3, with socket, 13 cm diameter (Is. 7d.); 9. Fork, h, for carry- ing Bunsen burner or Berzelius lamp, with socket (1 s. 7 d.). 51.104 a. Bunsen Burner for above, with air neck-piece, star, chimney, forked piece and soldering tube device 0. 3. 6 51.105. Universal Double Socket, for the universal stand (W. D., Fig. 36. -- M. T., p. 10) 0. 3. 6 51. 105 a. Westien Universal Clamp (W. D., Fig. 37. — M. T., p. 10) 0. 3. 6 51.106. Heavy Iron Tripod, with iron rod, 1 m long, suitable for the clamps listed under Nos. 51,104, 2 — 9, 51,105, 51,105 a, for clamping long tubes, etc 0. 3. 0 51.107. Bunsen Universal Stand, light construction 0. 15. 0 51,108. Precision Work Stand (Weinhold's) (W. D., pp. 37 and 38, Figs. 38—40), carefully constructed, thus ensuring the accessory p;irts being accurately and firmly clamped . The stand consists of 1 iron tripod with rod, 2 brass sockets with pressure screws, 1 small clamp with socket, 1 large clamp with socket, 1 retort holder, 1 clamp for cylindrical or prismatic objects (Fig. 39), 1 r.lanip" for conical, wedge-shaped or pyramidal objects (Fig. 40), 3 iron rods of 10, 30 and 50 cm length, 1 box for taking the accessories, 1 ring for funnels, 1 ebonite-rod for Geisslers nilie^. 1 rod 3. 10. 0 for suspending thermometers, 1 support to allow of using the stand in horizontal position, 1 clamp for holding tubes and rods, 1 clamp with tongs, 1 retort hold. Cl. 5488. No. 51118. Work Stands, Clamp Stands. 203 51104. 1:9. 51110. 1:6. 51111. 1 : 8. 51112. 1:10. 51114. 1:0. 51116. 1:3. 51117. 1 : 3. 51119. 1:8. 51.109. Stand with stays (Weinhold's) (W. D., Fig. 41), without weight 51.110. Retort Holder, Figure, with wood clamp and iron foot (W. D., Fig. 32) . . . 51.111. Filter Stand, iron, Figure, with two different size rings (W. D., Fig. 33) ... 51.112. Boiling Stand, iron, Figure (W. D., Fig. 34) 51.113. Cooler Stand, iron, F i g. 51,241, p. 211 (W. D., Fig. 44 [40]) 51.114. Burette Stand (Kaehler's), with universal holder for 2 burettes, with brass rod, Figure Burette Holder, brass, double-arm, with fixed arms, Figure Burette Holder, brass, two-arm, with movable arms, Figure (Hofmann's) . . — idem, brass, single-arm, with semi-circular arms, Figure Stand for preceding burette holders, iron tripod with brass rod, 13 mm diameter £ 8. d. 1. 16. 0 0. 5. 0 0. 5. 6 0. 3. 6 0. 5. 0 0. 9.0 0. 3. 6 0. 4. 0 0. 3. 0 0. 3. 0 0. 4. 0 Cl. 5855, 3872, 5513, 102, 5856, 101, 103, 104, 105. 204 Apparatus, Supplies and Materials for General Use. No. 51120 — 51 120 A. 1:7. 51139. 1:8. 51124. 1:15. f 51 120 B. 1:7. 51128. 1:18. 51120C. 1:7. 51126. 1:10. .li'o. Universal Clamp, Fi g s. A, B and C, for clamping reading telescopes as in Fig. A, £ a. «l scales as iii Fi-. I',, and rods, thermometers and the like, as in Fig. C, etc. . . . . 0. 9. 0 .-.l.lL'l. American Clamps, Figure, of iron (W. D., Fig. 45 [41]), 10 cm s pan 0. 2. 6 51,122. - - i d e 111, spaii i:> cm 0. 3. 6 ."i 1.1 23. -- idem, span 20 cm 0. I. (i •r>U2l. Gauss Stand, heavy construction, F i gu re. of oak, metal parts of iron, table with prismatic -uidc adjustable \crticidly (VV. I)., Fig. 30), with table, 40cm diameter; height, nnextended, 8H cm, extended. 1 lo cm 200 Cl. 5313,',5315, 5314, 110, 153, 106, 107, 3808. Nr. 51 H4. Clamps, Table Stands, Levelling Boards. 205 51132. 1: 8. 51133. 1 : 8. 51134. 1: 8. 51130. 1 : 15. 51 131. 1 : 14. 51142. 1:9. 51,125. -The preceding, iron parts entirely excluded from construction 5 J , 1 26. - - The preceding, table adjustable by rack and pinion, Figure, metal parts of iron - 51.127. -- idem, iron-free pattern 51.128. Laboratory Stand, lighter pattern, Figure, with table top, 50 cm diameter, ad- justable by crank motion, metal parts of iron 51.129. -The preceding, free from iron . 51.130. Gauss Stand, light pattern, Figure, of oak, free from iron, without crank motion, table top 30 cm diameter 51.131. --The preceding, simpler, fixed by pegs, Figure Tables for setting up apparatus, Figures (W. D., Fig. 31), with iron foot, brass pillar and polished wood top 15 cm diameter. List No. 51,132 51,133 51,134 Adjustable from 20 — 30 25 — 40 35 — 50 cm height £ 0.6.0 0.7.0 0.8.0 •The preceding, iron-free, with zinc tripod (M. T., p. 9). List No. 51,135 51,136 51,137 Adjustable from 20 — 30 25 — 40 35 — 50 cm height £ 0.8.0 0.9.0 0.10.0 The preceding, with double extension, thus increasing the range of adjustment, Fig. 51,139, -p. 204. List No. 51,138 51,139 51,140 Adjustable from 22 — 50 30 — 60 35 — 85 cm height £ 0.12.0 0.14.0 0.16.0 51.141. Adjustable, rotary Table for prisms, etc 51.142. Levelling Board and Slate Slab, in oak frame, Figure, 50 cm long, 30 cm wide, with 4 levelling screws, quite plane, for erecting apparatus 51.143. - - The preceding, with cast iron top, 50 cm long, 35 cm wide, planed, with 4 levelling screws , £ s. (I. 2. 5. 0 3. 5. 0 3. 15. 0 3. 2. 0 3.12. 0 2. 0 0 0. 18. 0 51,144. Levelling Board, round, 30 cm diameter, with 3 levelling screws. 0. 15. 0 1.16. 0 1.12. 0 0. 10. 0 Kl. 108, 3909, 5556, 152. 206 Apparatus, Supplees and Materials for General Use. No. 51145 51145. 1:10. 51151. 1:15. 51153. 1:12. 51.145. Levelling Board with micrometer adjustment, Figure, for accurately setting up apparatus which have no levelling screws fitted, and for adjusting at small angles (M. P., Vol. 1, Fig. 73), with small discs for supporting the levelling screws. Without spirit level The top is of plane glass in a metal frame; the levelling screw, in the form of a micrometer screw, has a disc graduated in degrees. 51.146. Parallelepipedic Wood Blocks, 15 cm square, 1, 2, 2 and 5 cm thick 51.147. Wood Supports, 15 cm square, 0.5, 1, 2, 2.5 and 10 cm high (M. T., p. 9). . . . 51.148. 2 Support Boxes with hole for gripping (M. T., p. 9), 20x30x40 cm 51.149. 1 Set of thin wood wedges serving as supports, 6 in set 51.150. 4 Wide wood wedges, 5 x 15 cm, width of back 0.5 and 1 cm (M. T., p. 10) ... 51.151. Frame Stand, of oak, Figure (W. D., Fig. 27), 1 m wide, 1 m high, with 8 small and 2 large hooks for suspending pendulums, levers, Magdeburg hemispheres, electro- magnets, etc. The frame can be taken apart. Price does not include experimental apparatus 51.152. Portable Gallows for suspending heavy objects and for tensile tests, as suggested by Friedr. C. G. Miiller (M. T., Fig. 3) 51.153. Mirror, on stand, Figure, for demonstrating phenomena in the horizontal plane, e. g., Chladni's harmonic figures, before a large audience (M. T., p. 9) This mirror is inclined towards the stand at an angle of 45 °. Flexible Leads, Figure (W. D., Fig. 493 [468]), covered with wool and braided with copper wires at ends. Cross-section, sq. mm 1.5 For currents to amperes 14 51.154. - - Length 0.60 m, Price Is. 51.155. - - Length 0.90 m, Price 1 s. 3 d. 51.156. - - Length 1.20 m, Price. ..... 1 s. 6 d. 51.157. - - Length 1.50 m, Price 1 S. 9 d. These flcxibles can be thoroughly recommended on account of the convonioncc of manipulation. Thicker leads quoted for on application. .~>l.ir>s. 1 Set Flexible Leads, comprising two lengths each of 0.0 and l.l' in and 1.5, 2.5 and ti si|. inni cross-section - - 12 lengths in all :fi. 3S5H. :,| 208 Apparatus, Supplies and Materials for General Use. Xn. ,M 1^1 B 51181. 1 2. 51184. 1:4. 51193. 1:3. 51195. 1 : 6. 51209. 1:6. 51199. 1:4. 51201. 1:4. 51203. 1 -. 3. 51,181. Thermo-Regulator, Figure, to 50 ° C. . for accurately adjusting within limits of 20' The thermo-regulator is inserted in the apparatus to be heated in such wise that the portion filled with mercury can be completely heated. For transit purposes the tube D is packed by itself, IN place being taken by a wire with bungs of cotton wool, which closes the ascension pipe at a. Before UMIJJ; the regulator this wire is removed and the tube D inserted in such manner that the scale etched on the tube, and corresponding to the desired temperature, is covered by the surface of the metal cap d. r>1.182. - - The preceding, for + 20— 100 ° C r.1,183. -- idem, for + 20 °— 150 ° C 51,184. Bunsen Burner, F i g u r e, can be screwed apart for demonstration purposes, simple pattern, without tap but having air regulator 51,186. -The preceding, but with tap and air regulator 51. is?. Accessories for the previous gas burners Nos. 51,184 and 51,186, consisting of Nos. 51,188—51,192 51,188. Chimney, with holder r, 1. 1 v.i. Annex for carrying small dishes, watch glasses, <•)<• ."i 1. 1 '.tit. Sieve Annex, with numerous apertures above r>l.] !H. Crown Piece, with lateral openings, for obtaining a corona of flame .~i I. l!i:>. Slit Annex, for obtaining a wide flame ."> 1.1 '.»::. Iserlohn Burner (.Mast.- burner), with double draught channel. Figure 51, 104. Rabs Burner, with .'< movable tubes Cl. -r>4K(l, 11B, f>481, 5478, :,177. 1719, 5482, .r>483, 112. No. :>iL'ii;. Thermo-Regulators, Burners. 209 i 51206. 1 : 6. 51207. 1:7. 51214. 1:10. £ s. d. 0. 4. 6 51.195. Universal Gas Burner (Teclu's), with burner pipe 145 mm in length and 16 mm internal diameter, without the heads A, B, C, D, E By the method of air regulation peculiar to this type of burner it can be used either as a Bunsen or an automatic blast burner and it is very efficient in its action. The attachments illustrated above are very suitable for use with this type of burner: (A) mushroom-shaped burner for obtaining a regular distribution of the heat in evaporation work; (B) cross-slot attachment for boiling liquids in beakers, etc. : gives a large amount of heat over a small space; (C) slot attachment for heating and bending tubes, being of great utility for this work. In addition, the following can be supplied: (D) star-shaped attach- ment, and (E) chimney with holder. Attachment A BCD (star-shaped) E (Chimney with holder) £0.1.7 0. 1. 7 0. 1. 0 0. 3. 6 0. 1. 0 51.196. --The preceding, smaller, with burner pipe 100 mm in length and 10 mm internal diameter 0. 3. 6 Attachement A B C D (star-shaped) E (Chimney with holder) £ 0. 0. 11 0. 1. 3 0. 0. 7 0. 2. 0 0. 0. 10 5J,197. Gas Burner (Finkener's), with simultaneous regulation for gas and air, single-jet type 0. 3. 0 51.198. -- idem, with star, chimney and air neck 0. 4. 0 51.199. --idem, as No. 51,197, triple-jet, Figure, with separate regulation for each jet 0. 9. 0 51. 200. --idem, six-jet .0.16.0 51,20.1. -- idem, with 4 burners arranged in a row, with attachments for wide jets . . j 0.17. 0 51.202. Gas Burner (Dierbach's), horizontal burner with universal adjustment (M. T., p. 10) ! 0. 10. 0 51.203. Blast Burner for gas, Figure 0. 10. 0 51.204. - - idem, with sextuple flame, giving a large and very hot flame, Figure.. 0. 14. 0 51.205. Blast Burner for gas, Figure 0. 16. 0 51.206. Blast Burner for spirit, Figure, for the blowing table 0.10.0 51.207. Berzelius Lamp for spirit, with burner stand, Figure 0.12.0 Spirit Lamps, constructed of glass, with tube for filling and ground-in stopper, Fig. 51,209. List No. 51,208 51,209 51,210 51,211 Capacity 50 100 150 200 ccm Price £ 0. 0. 8 0. 0. 9 0. 0. 11 0. 1. 1 51.212. Spirit Lamp, of sheet brass, 75 ccm capacity, with wick-regulator 0. 1. 6 51.213. - - idem, capacity 150 ccm 0. 2. 0 51.214. Spirit Bunsen Burner, Figure, somewhat like a small Bunsen gas burner, with reservoir, lx/2 m metal hose and tripod j 0. 14. 0 51,216. Spirit Bunsen Burner, larger, corresponding to 4 Bunsen gas burners, with tripod . j 1. 2. 6 Cl. 3601, 3230, 5205, 130, 5450. 14 210 Apparatus, Supplies and Materials for General Use. No. .-ililT — 51228. 51234. 1:4. 51252. £ s. d. 51,217. Star Burner Attachment and Wide Burner Attachment for No. 51,216 0. 1. -' 51.220. Tripod, iron, 100 mm internal diameter of ring 0. 1. (> 51.221. --idem, 120 „ „ „ „ „ 0. 1. 1 51.222. --idem, 150 „ „ „ „ „ 0. 1. 4 51.223. Tripod with 2 inset plates, Figure, of iron 0. 3. 0 51.224. Wire Triangle 0. 0. 1 51.225. - - idem, covered with small clay tube: 50 60 80 mm side of triangle £ 0. 0. 2 0. 0. 21/, 0. 0. 3 51.226. Wire Net, of i r o n, 10 cm square 0. 0. 4 51.227. Wire Net, of b r a s s, 10 cm square 0. d. 5 51.228. Wire Nets, of asbestos wire, Figure, cap-shaped, for Bunsen stands; can also be used as supports for beakers, flasks, evaporation dishes, crucibles, etc. which are being heated. One Set comprising one each of 7, 10 and 13 cm diameter 0. 3. 0 51.229. Air Bath, Figure, Ostwald's, with lighting flames, round type 0. .">.<) 51.230. -- i d e m (Muck's), rectangular, Figure, with arrangement for heating. . . . 1. !.">. o 51.231. Asbestos Dishes (M. T., p. 11): Diameter cm 10 15 20 0. 0. 4 0. 0. 7 0. 0. 10 51.232. Water Bath, of copper, with insertion rings, Figure, 20 cm diameter 0. s. o 51.233. - - The preceding, with constant level, Figure, with insertion rings, plate with small apertures, cover and tripod 0. is. o 51.234. Evaporation Apparatus (Water Bath) (Loessner's), without rings, with iris adjustment, constant level, on tripod 1. 1. 0 Electrically-heated Water Baths, Figure, hemispherical, constructed of copper, with copper inset rings, for 100 — 110 volts, 4 — 7 amperes. List No. 51,235 51,236 51,237 51,238 Diameter cm 12 15 18 '22 Price £ 1. 18. 0 2. 4. 0 2. 10. 0 2. 16. 0 The water baths can be supplied for either direct or alternating current voltages up to 250 volts. \Vlion ordering, kindly mention voltage available. Coolers (Liebig's), Fig. 51,241, with funnel pipe and brass jacket, on massive stand. List No. 51,239 51,240 51,241 Size cm 40 55 65 Price £ 0. 15. 0 0. 16. 0 0. 18. 0 Cl. 324'.. M? :!L'4I!, I IT '. I 4.'.. 136. No. 51 •£-.. Supplies for Warming and Cooling. Gasometers. 211 51250. 1:10. 51 243. 1 : 8. 51256. 1:12. 51257. 1:10. Sand Baths, Figure 51,243, comprising: sheet metal dish with iron stand, heating coil ad- justable vertically, with gas lead from both sides for obtaining an even flame. List No. 51,242 51,243 Size of Dish cm 25 x 15 40 x 20 Price £ 0. 12. 0 0. 14. 0 Calibrated Glass Bells for measuring gas volumes (M. T., Fig. 5), with clamping rings. List No. 51,244 51,245 51,246 51,247 51,248 51,249 Capacity ccm 100 250 500 1000 1500 2000 Size about cm 220x30 280x40 360x55 450x65 470x75 500x80 Price £ 0. 6. 0 0. 7. 0 0. 8. 0 0. 10. 0 0. 12. 0 0. 14. 0 51.250. Mercury Gasometer, Figure, with double-wall mercury chamber, collecting bell, oak stand, without mercury, for 250 ccm 51.251. --idem, for 1000 ccm 51.252. Gasometer (Pepys'), of stout lacquered sheet zinc, Figure, 30 1 capacity . . . 51.253. - - i d e m, 50 1 capacity 51.254. --idem, of copper, 30 1 capacity, cf. F i g. 51,252 51.255. --idem, 50 1 capacity 51.256. Gasometer, of glass (Mitscherlich'p), Figure, with metal fittings, 15 1 capacity 51.257. --idem, 25 1 capacity, Figure Cl. 5484, 148, 146, 3229, 3911, 3250, 137, 138. £ S. d. : 1. 0. 0 1. 5. 0 2. 5. 0 3. 0. 0 3. 0. 0 4. 0. 0 2. 0. 0 3. 0. 0 14* 212 Apparatus, Supplies and Materials for General Use. 51258. 1:11. 51261. 1:12. 51266. 1:13. Bell Gasometer, Figs. 51,258 and 51,261, with loading and unloading weight, the larger apparatus having guide rods for the weight. £ s. d. Capacity litres Of stout, i List No. lacquered sheet zinc \ Price £ O, 9heet copper { 50 75 100 150 51,258 51,259 51,260 51,261 3.10.0 4.10.0 6.0.0 8.0.0 51,262 51,263 51,264 51,265 5.0.0 6.0.0 7.10.0 11.10.0 51.266. Universal Gasometer (Dr. Eichhorn's), Figure, for 120 1 volume, with water gauge, pressure gauge and regulating cock (Ztschr. f. d. phys. u. chem. U., 4, 1891, p. 325) The regulating cock has a pointer moving over a large dial, and has 5 positions marked in plain lettering on same: (a) water and gas cut off, (b) water on, gas off, (c) water on, gas out, (d) water off, gas out or in, (c) water out, gas in. The apparatus can be used (1) as an ordinary gasometer, ('2) as a blower, (3) as a force pump, (4) as a suction apparatus and exhaust pump. 51.267. Rubber Bag, well constructed, Figure, for 110 1 oxygen, with tap and clamping board 51.268. --idem, for 165 1 content 51.269. - - idem, for 210 1 content ."• 1.270. --idem, for 280 1 content. . . . 51,271. Aspirator, of sheet zinc, with brass stopcock, with 1 vessel. Figure, 51 content .".1.272. -- idem, 10 1 content r. 1.2 73. Aspirator, with 2 vessels, Figure, 51 content r.l 274. - - i <1 em, 10 1 content .">1,27.">. Aspirator, with 2 vessels rotary on a horizontal nxis, Figure, 5 1 content . . 51, 276. — idem, 10 1 content 6.10.0 5. 0.0 ti. 5. ii 7. 10. 0 10. 0. 0 0. U. 0 1. 0.0 0.18.0 1. 4.0 2.10.0 3. 5.0 l. 5891, :iL'!7. 140, 141. No. .M2S.1. Gasometers, Aspirators, Gas- and Steam-Generating Apparatus. 213 51279. 1:7. 51285. 1:5 51 278. 1 : 7. 51,277. Aspirator, Figure, with 2 glass flasks, tubulated, adjustable vertically, and of 12 1 content, with oak stand and braided rubber hose 51,278. Gas Generating Apparatus (v. Babo's), Figure, with rubber stoppers and gas conduit pipes 51,279. Gas Generating Apparatus (Bardeleben's), Figure, consisting of a wide glass cylinder with bell and inset vessel, brass cover, stiiffing box and glass stopcock . . Gas Generating Apparatus (Kipp's), F i g. 51,282, with rubber stoppers. List No. 51,280 51,281 51,282 51,283 Capacity ccm 250 500 1000 2000 Price £ 0. 7. 6 0. 9. 0 0. 10. 0 0. 13. 0 51,284. Hydrogen Generating Apparatus, Figure, consisting of 2 tubulated flasks, rubber hose, drying bulb with stopcock and adjustable stage. The apparatus can be, connected direct to the burner . 51,285. Weinhold's Steam Boiler (W. D., Fig. 49 [45]), of sheet brass, Figure £ s. d. 6. 5. 0 0. 18. 0 1. 5. 0 0. 18. 0 0.16. 0 (1. 1 12. 11:1, in, il'.uo, 5875, 133, 149, 132, 3612. 214 Apparatus, Supplies and Materials for General Use. NO. 51287. 1:4. 51293. 1 : 5. 51288. 1 = 7. 51294. 1:3. 51297. 1:3. 51301. 1:5. 51,286. American Freezer, Figure, for making pure ice or preserving ice by a cold mixture; £ s- d- freezes 1V2 1 water in 15 minutes, or ice-cream in 8 to 12 minutes. Convenient to handle. With description and recipes 0. 12. o The refrigerating medium in these machines is a mixture of ice or snow with salt. ."•1,287. Ice Chopper for above, Figure 0. 1. 6 51,288. Ice Machine (Liebreich's), Figure, for making small quantities of absolutely pure ice; produces 500 — 600 g ice in 15 minutes 1. 16. 0 The action of this machine is based on the fact that ammonium nitrate takes up heat on going into solution so that the temperature falls about 25° C. The ammonium nitrate necessary for making the ice is recovered by evaporation of the solution, and the ice is therefore very conveniently and cheaply produced. — Ice and salt are not used for freezing in this machine. ."•l.L'89. --The preceding, for making from 1000 to 1200 g in 15 minutes .... 3. o. o 51,290. Enamelled kettle for the volatilisation of the ammonium nitrate 0. !». o ."•I. •_'!»!. Vessel for preserving the ice blocks 0. 11. «> 51,292. Mercury, chemically pure and dry Per kg 0. s. u ">l.i'!t:5. Mercury Board, Figure, can be used as a tray, 60x40 cm 0. 7. 0 The mercury tray is intended for taking the apparatus involving the use of mercury so that any mercury which may be spilled is collected on the board. The board is of oak, and has a raised edge 30 mm in height and, in one of the corners, an escape hole. ci. l HI. is:.. 1. V.. 1SI1. Ice Machines, Supplies for Work with Mercury, other Supplies. 215 51302. 1:6. 51 305. 1 : 2. 51306. 1:3. 51307. 1:3. 51308. 1 : 3. 51 303. 1 : 5. 51304. 1:6. 51312. 1 : 4. 51.294. Mercury Box, Figure, with outlet and screwed cap, constructed of box-wood, £ s. d. with ivory top; capacity 1 kg 0. 5. 0 This box is very convenient to handle, the mercury being kept perfectly clean. 51.295. --idem, 3 kg capacity 0. 6. 0 51.296. --idem, 5 kg capacity 0. 7. 0 51.297. Mercury Box, of box-wood, with steel tap, 1 kg capacity, Figure 0. 9. 0 51.298. --idem, 3 kg capacity 0. 10. 0 51.299. --idem, 5 kg capacity 0. 12. 0 51.300. Mercury Dropping Vessel (Grimsehl's), Figure (Ztschr. f. d. phys. u. chem. U., 18, 1905, p. 34). Price without mercury 0. 1. 2 51.301. Mercury Capillary Dropper, Figure, for pouring out small quantities of mercury . 0. 4. 0 51.302. Mercury Trap, Figure 0. 10. 0 This device is let into the floor and takes up the small quantities of mercury which have spurted and collected together. The mercury can easily be removed from the trap by means of the inner chamber. 51.303. Mercury Tongs, Figure, for picking up drops of mercury 0. 2. 6 51.304. Mercury Press, Figure, for purifying mercury 0. 12. 0 51.305. Tweezers, German silver, double, with platinum tips, Figure . . 0. 6.0 51.306. Tweezers, brass, simple pattern, with bent ivory tips, Figure 0. 1. 6 51.307. Tweezers of brass, simple pattern, Figure 0. 0. 6 51.308. Crucible Tongs, iron, lacquered, Figure 0. 0.10 51.309. --idem, of iron, polished 0. 1. 0 51.310. --idem, of German silver 0. 2. 0 Spatulas, double-sided, of polished steel, Fig. 51,312. List No. 51,311 51,312 51,313 51,314 Length cm 12 21 29 40 Price £ 0. 0. 4 0. 0. 6 0. 0. 10 0. 1. 6 Spoons, with spatulated handle, of nickel. List No. 51,315 51,316 51,317 Length cm 12 15 21 Price £ 0. 1. 2 0. 1. 6 0. 2. 6 51.318. Spoon, of glass, 20 cm long 0. 0. 8 51.319. Phosphorus Spoons, of iron 0. 0. 4 51.320. Mortar, cast iron, with pestle, hollowed out, 15 cm diameter, 15 cm high .... 0. 15. 0 51.321. Agate Mortar, with pestle, external diameter 65 mm 0. 8. 0 51.322. Pulverising Dishes with spout and mortar. 70 100 130 mm diameter £ 0. 0. 10 0. 1. 1 0. 1. 6 Cl. 173, 3252. 4019, 171, 17:">, 5466, 3253, 4020, 15s. :;;;:,«. 216' Apparatus, Supplies and Materials for General Use. NIL 51323. 1:5. r 51325. 1:5. 51334. 1:2. 51326. 1:3. 51328. 1:3. 51331. 1:5. 51.323. Blowpipe, collapsible, the tip having platinum discs, Figure 51.324. -- idem, collapsible, simpler, withoiit platinum tip 51.325. — idem, not collapsible, Figure 51.326. Cork Borers, brass, 12 in set, Figure 51.327. Cork Borers, brass, 9 in set set, Figure set set . 6 6 12 in in in 51332. 1:5. £ 0. 0. 0. 0. 0. 0. 0. 0. 51.328. Cork Borers, brass, 51.329. Cork Borers, steel, 51.330. Cork Borers, steel, 51.331. Cork Boring Apparatus, Figure, for firmly screwing to table, with 8 nickelled steel piercers of 4 to 15 mm diameter 51.332. --idem, Figure, with srcew clamps for screwing on to edge of table .... 51.333. --idem, larger pattern, with screw clamp and with 15 nickelled steel piercers of 4 to 25 mm diameter 51.334. Sharpener for cork borers, Figure 51.335. Cork Press, Figure 51.336. Rubber Stoppers, various sizes, 16 in set No. 1 Diameter above 10 Diameter below 7 Length 20 Each */z d- No. 9 Diameter above 28 Diameter below 22 l-etigth 28 Each 6 d. For piercing the stopj 51.337. 100 Corks of various sizes, conical (M. T., p. 10) 51.338. 10 Glass Stoppers for closing hose and holes in corks (M. T., p. 10) 51.339. Pneumatic Trough for Water, of stout double glass, in brass frame, with adjustable bridge of plate glass. Trough is 320 mm long, 160 mm wide, H.T) mm high .... -">!.:; Hi. Glass Receiving Cylinder, Figure, tall form, with unpolished edge, without -toppers and migniduated Per set of 5 Si/e mm 150x40 175x50 200x60 250x60 300 -SO £ 0.0.6 0.0.8 0.1.0 0.1.1 0.1.10 M..U1. Measuring Cylinders with lip Figure. I'er set of 10 10 25 50 100 150 200 L'.M) 500 1000 L'OOOrrm capaeit y 6d. 9d. lid. Is. 3d. Is. 6d. Is. 7d. Is. lOd. 2s. 3d. 4s. Id. 7s. Id. Cl. 1 :.». 2 3 4 5 6 7 8 12 15 16 18 20 23 25 mm 9 10 12 14 16 20 22 „ 21 20 22 22 20 30 30 „ Id. Id. IV. a. 2d. 3d. 4d. 64. 10 11 12 13 14 15 16 30 31 35 40 42 45 50 mm 24 27 30 35 37 40 43 „ 30 30 33 33 33 33 35 „ 6d. evsd 1. 8d. Is. 1 s. 1 d. 1 s. 3 d. 1 s. 6 d. the n rice for each hole is 0. 0 2. 0 12. 0 1. 6 3. 6 8. 9 2. 6 0. 6 0. 0 5. 1 1. 1. !» 17L'. li;-. It,1.'. N.I. :.l 358. Cork Borers, Stoppers, Hollow Ware. 217 51335. 1:5. 51351. 51348. 1:2. 51340. 51345. 1 ; 6. 51341. 51 342. 51354. 1:2. 51 342. Measuring Glasses with stopper (mixing cylinders), Figure, graduated in com. £ s- d. Per set of 6 0. 16. 1 100 150 200 250 500 1000 ccm capacity £ 0.1.7 0.1.11 0.2.1 0.2.5 0.3.0 0.5.1 51.343. Preparation Cylinders, with wide stopper ground in (M. T., p. 11). Price per set of 3 0. 2. 6 100 200 400 ccm capacity £ 0. 0. 7 0. 0. 10 0. 1 1 51.344. Base for measuring glasses (Eebenstorff's), (Chemiker-Ztg., 1908, p. 177) ..... 0. 3. 6 51.345. Beakers, Figure. 6 8 10 12 in set £0.1.1 0.1.9 0.2.7 0.3.10 51.346. Test Glasses. One set of 30, 3 sorts 0. 1. 7 100 150 180 mm high 16 16 20 mm diameter £ 0. 0. 5 0. 0. 6 0. 0. 8 per set of 10. 51.347. Test Glass Stand, unpolished, for 12 glasses, with rods for drying the glasses ... 0. 1. 6 51.348. Test Glass Holders, Figure, of nickelled clockspring steel 0. 0. 7 51.349. Watch Glasses. Per set of 4 0. 1. 3 50 65 80 100 mm diameter £ 0. 0. 2V2 0.0.3 0. 0. 3V2 0.0.6 each. 51.350. Watch Glass Clamps, 1 set, suitable for preceding glasses, of sheet brass 0. 1. 3 51.351. Crystallising Dishes, Figure, set of 10, 40 — 160 mm diameter, with lip .... 0. 6. 0 51.352. Porcelain Dishes, with lip, Figure. Set of 6 j 0. 2. 0 60 70 85 100 125 155 mm diameter £ 0. 0. 2V2 0. 0. 2V2 0.0.3 0. 0. 3V2 0. 0. 5V« 0.0.7 each. 51.353. Porcelain Crucibles, with lids. Price per set of 8 0. 4. 4 3 10 18 30 65 90 135 220 ccm capacity 21/,d. 2V,d. 3d. 4d. 6 d. 7 d. 9 d. Is. 6 d. each. 51.354. Holder for Porcelain Dishes and Crucibles, Figure, of nickelled clock spring steel 0. 0. 7 51.355. Iron Dish, flat, 80 mm diameter 0. 0. 4 51.356. - - idem, 100 mm diameter 0. 0. 5 51.357. -- idem, 150 mm diameter 0. 0. 7 Deep dishes are charged for at double the above prices. 51.358. Carbon Crucible, 50 mm high, 45 mm diameter . 0. 1. 0 tl. oJWi. 17(1, 179, 181, 5467, 162, 164, 5465, 180. 218 Apparatus, Supplies and Materials for General Use. No. 51 3.V.I — 51 367. 1 : 4. 51374. 1:7. 51 386. £ s. d. 51.359. Magnesite Crucible, 50 mm high, 45 mm diameter 51.360. Carbon Dish, 65 mm diameter 51.361. - - idem, 100 mm diameter 51.362. Graphite Dish, 150 mm diameter 51.363. 10 Smelting Crucibles, of fire clay, 5 different sizes 51.364. Hessian Crucibles, of clay, triangular, without lids. Per set of 3, 8 cm high . . . 51.365. — idem, set of 5, 12 cm high • 51.366. --idem, set of 7, 17 cm high Platinum Crucibles in any desired size and shape. Prices vary according to weight and prevailing price of platinum. 51 367. Stand for Platinum Crucibles and Dishes, Figure, for setting on Bunsen burners, adjustable for different sizes, with vertical adjustment and wind screen. Price, subject to alteration without notice This stand is for placing on the burner, and with its aid platinum dishes and crucibles of any size can be firmly fixed without any bulging. The crucibles are hung in platinum slings and they do not, therefore, even at high temperatures, come into contact with other metals. 51.368. Powder Jars with wide neck, Figure, with grips or flat stoppers of white glass. Price, unfilled: 150 200 300 400 500 1000 ccm capacity (a) With Grips . . . 3 s. 3 d. 3 s. 9 d. 5s. 5 s. 6 d. 6 s. 6 d. 10 s. per 10 (b) With Flat Stoppers 4s. 4 s. 7 d. 6s. 7s. 8s. 12 s. per 10. If without stoppers the bottles cost about half the price charged for these with squat stoppers. 51.369. Bottles for Liquids, with narrow necks, with tall or squat stoppers, F i g u r e, of white glass. Price, empty: 150 200 300 400 500 1000 ccm capacity (a) With drips . . . 2s. 3d. 2s. 6 d. 3s. 6 d. 4s. 4s. 10 d. 7 s. 6 d. per 10 (b) With Flat Stoppers 3s. 3 s. 6 d. 4 s. 6 d. 5 s. 3 d. 6 s. 4 d. 9 s. 6 d. per 10 51.370. Bottles for Reagents or Powders, with enamel labels, burnt-in black or etched inscrip- tions, with tall or squat stoppers and wide or narrow openings, Figure. 100 150 200 300 400 500 1000 grams capacity Is. Id. Is. 2V2d. Is. 3V2d. 1 s. 5 d. Is. 6Vs& Is. 8'., d. 2 s. 1 d. each. Prices 10% extra for brown or blue glass bottles. (I. 1. 0 0. 1. 0 0. 1. 0 0. 3. 6 0. 3. 6 0. 0. 3 0. 0. 6 0. 1.0 0. 15. 0 ( ]. Hi:.. 1W. .M'.i- No. :.! 399. Hollow Ware, Drying Apparatus. 219 51378. 51379. 51382. 51389. 51 397. 1 : 5. Reagent Stands with Reagent Bottles, F i g. 51,374, of polished wood. List No. 51,371 51,372 51,373 51,374 Number of bottles without contents . 24 32 40 48 (a) In Alder Wood £ 2. 15. 0 3. 5. 0 3. 15. 0 4. 5. 0 (b) If in Mahogany or Oak .... £ 0. 7. 0 0. 8. 0 0. 9. 0 0. 10. 0 extra. These stands have two drawers and 3 — 5 stages for taking the bottles of 33 — 125 com volume, the bottles having well fitting squat stoppers. The inscription is burnt into these bottles. List of inscriptions on application ; the inscriptions are also prepared according to instructions supplied by clients. 51.375. Rotary Reagent Stand for placing on the table. Price, without bottles 51.376. Boiling Flasks, long-necked, or with short necks strengthened at the upper edge 250 21/, d. 400 3d. 500 3V2d. 8d. 500 41/, d. 7V, d. 10 d. 1000 51/, d. Is. ccm capacity (Per set of 7) (Per set of 5) 1000 ccm capacity. 1 s. 2 d. 100 150 200 IV, d. I1/, d. 21/, 51.377. — idem, of refractory glass. 4 d. 5 d. 7 d. Measuring Flasks, with a mark on neck. 25 50 100 250 51.378. — Without stoppers, Figure: 5 d. 4 d. 51.379. — With stoppers, Figure: 7 d. 6V2 d. 7 d. 11 d. 1 s. 2 d. 1 s. 6 d. Woulff Flasks. Content 1 1.5 2 3 litres 51.380. - - with 2 or 3 necks 1 s. 6 d. Is. lid. 2 s. 6 d. 3 s. 3 d. 51.381. - - with 2 or 3 necks and tube at bottom . 2s. 2 s. 5 d. 3 s. 3 d. 4s. 51.382. Retorts, without tube, Figure. Per set of 6 100 150 250 400 500 1000 ccm capacity Each 21/, d. 3d. 4 d. 5 d. 51/, d. 7d. 51.383. - - idem, with tubulure and ground-in stopper. Per set of 6 100 150 Each 5V2d. 6 d. Retorts of refractory glass. 250 7V, 400 9d. 50 500 10 d. 100 4cl. 6d. 100 1000 ccm capacity 1 s. 1 d. 250 6 a. 9d. 250 4d. 6d. 7d. 500 ccm 10 d. Per set (4) 1 s. 1 d. Per set (4) 500 ccm Per set (3) Per set (3) Per set (3) 6d. 7d. 10 d. 51.384. - - without tube 3d. 51.385. - - with tube, without stopper ... 5 d. Receivers for Retorts. 51.386. - - without tube. Figure 3d. 51.387. - - with 1 tube 4 d. 51.388. - - with 1 tube and ground-in stopper ... 5 d. Oxygen Generating Retorts (see Nos. 50,960 and 50.961, p. 174) 51.389. Funnels. Figure. 50 IV. d. 51.390. Funnel Tubes (Safety Tubes). 200 3 IV, d. 21 51.391. Safety Funnel with bulb 51.392. - - idem, with 2 bulbs 51.393. Separating Funnels, round, with stoppers. V4 V2 1 \itre capacity 3s. 3 s. 6 d. 4 s. 3 d. each. 51.394. Drying Cylinder (calcium chloride cylinder), as suggested by Fresenius, 250 mm high 51.395. Drying Tubes (Schmitz') (Fresenius, Ztschr. f. analytische Chemie, 23, 1884, p. 515) 51.396. Desiccators (Fresenius'), with ground-on cap and glass triangle, 80 mm diameter, cf. Fig. 51,397 51.397. - - idem, 100 mm diameter, Figure 51.398. - - idem. Scheibler's, with glass lid, 120 mm diameter, with porcelain inset . 51.399. - - i d e m, for evacuating, with glass stopcock, glass plate and porcelain inset . . ) 120 155 mm aperture 1. 3V2d. 5d. Per set (4) 00 400 500 mm tube-length /2 d. 3 d. 4d. Per set (4) £ s. d. 1.10. 0 0. 1. 8 0. 3. 0 0. 2. 3 0. 4. 3 0. 1.11 0. 2. 9 0.1. 1 0. 1. 5 0. 1.10 0. 1. 0 0. 0.11 0. 0. 5 0. 0. 6 0. 1. 0 0. 4. 0 0. 3. 6 0. 4. 0 0. 5. 0 0. 8. 6 Cl. 177, 178, 547L', .M70, 5171. 220 Apparatus, Supplies and Materials for General Use. N.I. :.i Km 51412. 1 : 2. 51416. 1 : 10. 51414. 51.400. Spray Flask (Fresenius') (W. D., p. 60 [54]) . . . . 51.401. Hardened Filters Per set of 50 Diameter cm 4 7 11 15 24 Per 10 2V« d. 3V2 d. 7 d. 10 d. 1 s. 6 d. 51.402. Filter Paper, medium thick, absolutely white and specially pure; also suitable for liquids difficult of filtration, 58 X 58 cm size. Price per 100 sheets 51.403. Gas Washing Flasks, Bunsen's. 250 500 ccm capacity £ 0.0.10 0.1.0 51.404. Combustion Boat, porcelain, 40x5 mm 51.405. - - idem, larger, 62 x 7 mm 51.406. Bent Tubing Per kg 51.407. Spherical Tubes (M. T., p. 11), with 123 bulbs . . Per set (3) 6 d. 7V2 d. lOVs d- 51.408. Combustion Tubes, thickness of wall, abt. Vioth of the diameter, in lengths of 1 in. Per kg 51.409. U-Tubes (desiccating tubes) (M. T., p. 11). Per set of 3 80 130 180 mm length of limb £ 0.0.3 0.0.4 0.0.6 51.410. Stirring Rod, glass, 25 cm long, with round-fused ends 51.411. Overflow Pipettes Per set (9) 1 2 5 10 20 25 50 100 200 ccm 4 d. 4 d. 41/,. d. 5 d. 6 d. 71/. d. 9 d. 11 d. 1 s. 3 d. 51.412. Pipette, for small vessels and tubes the lower orifice of which is plunged in a liquid Burettes (Mohr's). 51,413. 25 V: in 50 V. 75 100 ccm capacity Vs V» ccm graduation with pinch cock, see Fig. 51,119, p. 203. 1 s. 7 d. 2 s. 6 d. 3s. 4 s. 6 d. 51.414. -- with glass stopcock, Figure. 2 s. 8 d. 3 s. 6 d. 4 s. 4 d. 4 s. 8 d. 51.415. Floater for above 51.416. Demonstration Gas Burette (Bunte's), modified by Bischbieth, Figure (Ztschr. f. d. phys. u. chem. U. 15, 1902, p. 74), 100 ccm capacity, graduated in fifths of a ccm, with stand. The burette tube has at the top a branch tap, emission tube and funnel for filling, with a simple tap at the bottom. The rubber tubing can be closed by a pinch cock. With platinum wires 51.417. Eudiometer (Bunsen's). 300 500 800 mm graduation £ 0.3.2 0.4.0 0.5.6 .1 ,418. 6 Brushes for reagent glasses, beakers, boiling flasks and measuring glasses (M. T., p. 11) 51.419. Picein (Walter's): a cement for assembling physical apparatus; quite insoluble in water and alcohol (Drudes Annalen d. Phys., Vol. 18, 1905, p. 860). Per 200 grams . . . 51.420. Various Materials for general purposes (as suggested by F. C. G. Miillci •; see No. 50,254, p. 40) 51.421. Glass Pearls, abt. 3 — 1 mm diameter (M. T., p. 11) Per kg 51.422. Glass Plates, round, ground matt one side, 50 — 210 nun diameter (M. T., p 10). Per set of 7 £ s. d. 0. 0. 7 0. 3. 5 0. 13. 0 0. 0. 4 0. 0. 5 0. 2. 0 0. 2. 0 0. 3. 3 0. 1. 1 • 0. 0. 3 0. 5. 6 0. 3. 0 '0. 0. 8 1. 4. 0 0. 9. 0 0. 2. 0 c. 10. o o. r>. o 0. 3. 3 ( I. No. 51436. Measurement of Lengths. 221 51423. 1:4. 51426. 1: 10. 51425. 1 : 12. 51433. 1 : 9. Measurement of Lengths, Angles, Surfaces and Volumes, Dividing Engines, Slide Rules. * 51,423. Linear Vernier Model for the projection lantern, with forward vernier, demonstrating £ s. d. barometer reading, Figure (Ztschr. f. d. phys. u. chem. U. 16, 1903, p. 345), with screw adjustment 1. 5. 0 * 51,424. - - idem, with rear vernier 1.5.0 51.425. Linear Vernier Model with forward and rear verniers, Figure, of wood (Fr. phys. Techn. I, 2, Fig. 2025) • 1. 0. 0 51.426. Linear Vernier Model, 1.10 m long, Figure, graduations on lacquered paper, with 1 cursor containing on one side the rear and on the other side the forward vernier (W. & E. phys. Prakt., Figs. 7 and 8. - - Gan.-Man. Fig. 54 and 55. - - Gan.-Eein. Fig. 1) 0. 10. 0 51.427. - - idem, \\einhold's, larger, 2.30 m long, with 2 cursors of 1 m length for the forward and rear vernier 1. 0. 0 51.428. Millimeter Rule, of thin cardboard, 500 mm long, with horizontal or vertical figures, or without figures (M. T., p. 24) Per 10 0. 3. 0 51.429. --idem, of wood, 500 mm long Each 0. 2. 0 51.430. Millimetre-Scale, paper pasted on wood, can be used vertically and horizontally, 50 cm long, with stand (M. T., p. 24) 0. 18. 0 51.431. Prismatic Rule, box-wood, 30 cm long 0. 1. 3 51.432. Metre Rule, wood, both sides graduated in millimetres, with brass bound ends . . 0. 3. 0 51.433. Metre Rule, wood, Figure, with coloured graduations in centimetres (W. D., Fig 46 [42]) 0. 2. 0 51.434. Ruler, white with black graduations and large figures, with 4 graduations: metres, yards, "saschen", "arschin" " 0. 15. 0 51.435. Mirror Rule for the class, 5 cm wide, 60 cm long, graduated direct on the glass in millimetres (Hahn, Handbuch fur physik. Schiilerubungen, p. 38. - - Kaiser, Physika- lische Schiileriibungen, p. 19), with wood stand 0. 16. 0 51.436. -- idem, simple pattern, graduations oh paper, with wood stand ....... 0. 10. 0 # Can be used with the Projection Apparatus. ' '£,£;_ r,-:i7 414.' 222 Measurement of Lengths, Angles, etc. No. 51437 — 51443. 1:11. 51457. 1:2. 51444. 1:10. 51.437. Steel Ruler, 1 m long (Standard Rule), divided on one side in millimetres and on the other in English inches, in case 51.438. Dividing Ruler, with steel angle rail, for rapidly dividing a length into 10 equal parts (Fr. phys. Techn., Vol. I, 2, Fig. 2018) 51.439. Standard Metre, divided in centimetres, of hard brass, 20 mm wide and 10 mm thick, the first decimetre being divided into millimetres. In box . 1 ,440. Standard Metre, of brass. Figure, with millimetre graduation on silver, for reading in conjunction with a telescope or microscope, extremely accurate, serving as comparing measure in physical experiments. In case 51.441. Standard Metre (H-section), with millimetre graduation on silver, the first and last millimetres being divided in tenths, lines of extreme fineness on the neutral stratum, for reading with the telescope or microscope This rule is massively constructed of a suitable metal alloy and is in accordance with the con- ditions laid down by the Bureau International for the standardisation of this class of rule. Standar- disation fee is quoted on application. 51.442. Carrier for suspending rules Nos. 51,439 — 51,441 vertically, with clamps and ad- justing device for the rule 51.443. Demonstration Rule, Figure, 1.15 m long, arranged for horizontal and vertical measurements 51.444. Vertical Rule, Figure, 1.2 m long, on iron stand, with cursor and pointer, with coloured centimetre graduation visible from a distance, and millimetre graduation, for conveniently measuring heights (W. D., Fig. 47 [43]) ."•1,445. -- idem, with graduation 2 metres long ."•1,446. - - idem (Bebenstorff's), 1 m long, with cursor, number scale and coloured scale in the German military colours (Ztschr. f. d. phys. u. chem. II. 18, 1905, p. 346). . In the coloured graduation from cm to cm gray signifies 0 and 5, white 1 and 6, red 2 and 7, yellow 3 and 8, blue 4 and 9. 51,447. Simple Vertical Rule (Grimsehl's), millimetre rule on iron base with brass cursor . s. d. 0. 0 0. 10. 0 4. 0. 0 7. 0. 0 10. 0. 0 6. 5. 0 1. 5. 0 0. 18. 0 1. 4. 0 0. 18. 0 0. 12. 0 (l. :,:IT.\ :i-j«», 416, 413, 448K, 154. No. 51402. Measurement of Lengths. 223 51459. 1:1. 51458. 1 : 1. 51460. 1:2. 51461. 1 : 5. 51,448. Vertical Rule for placing on wall (as suggested by F. C. G. Miiller: M. T., p. 23), with projecting end plate and spring cursor 51.450. Measuring Staff, 3 m in length (M. T., p. 24) 51.451. Tape Measure, 20 m long, with metre and inch graduation, in leather case, with turn-in handle 51.452. Indicator Cylinder (Miiller's), Figure, for the magnification of small variations in length (M. T., Fig. 4) 51.453. Curvimeter, Figure, for measuring the length of curved lines, with 3 graduations for scales of 1 : 15,000, 1 : 25,000 and 1 : 35,000, or with other graduations if required 51.454. Pedometer, watch form, nickelled, counting to 100,000 steps, with press-knob zero fly-back action, with 3 dials . 51.455. Wire Gauge, Figure, for wires from 0.01 to 1 mm diameter 51.456. Hole Gauge for cylindrical holes from 1 — 15 mm 51.457. Vernier Caliper, Figure, with vernier for the millimetre graduation, also with graduations in Khenish, English and Paris inches 51.458. Micrometer Gauge (Palmer's) (M. P. I, Fig. 52) for measuring thickness of wires, sheets and the like, Figure, 15 mm span, measuring accurately to 0.01 mm, with feeler screw which secures that always just the same pressure may be exerted. In case 51.459. - - idem, without feeler screw, nickelled, Figure, span 10 mm, reading 0.05 mm 51.460. Small Spherometer, Figure, with magnifying glass and black plate glass . . . 51.461. Spherometer (W. & E. phys. Prakt. Fig. 17), Figure, with micrometer screw of 0.5 mm pitch and head circle graduated in 500 parts, accurately measuring to 0.001 mm, with plate, glass base 51.462. - - idem, with feeler lever s. d. 15. 0 7. 0 12. 0 5. 0 8. 0 15. 0 5. 0 2. 6 0. 7. 6 12. 0 5. 6 10. 0 5. 0 15. 0 CI. WH, 419, 46H2, 5391. 224 Measurement of Lengths, Angles, etc. No. M 1113 — 51464. 1:11. 51466. 1 : 10. 51463. 1:12. 51468. 1:8. 22. 0. 0 51.463. Cathetometer, Figure, large, constant apparatus, telescope being regulated by £ s. d. micrometer screw, graduation on silver, capable of reading by vernier to Vso"1 mm; in- strument rotating on journals 65. 0. 0 Differences of height up to 1 m can be measured with the instrument; the prismatic, rotary pillar has micrometer adjustment and 2 levels at right angles. A Fraunhofer magnifying glass with micrometer and movable thread is fitted to the telescope slider for accurately reading the fine gradua- tion. The reading telescope has a level fitted. 51.464. Cathetometer, Figure, first-class construction, with massive prismatic pillar capable of rotation about its axis The pillar of the instrument is 1.15 m high, is divided in millimetres, and is provided with a vernier for V»oth mm. The telescope of 27 mm aperture, adjustable to any angle, and carrying a level, permits of making readings at distances of from 0.6 to 10 m. ."> 1.165. -- idem, telescope with micrometer screw and adjustable thread 51,466. Cathetometer, Figure, telescope of 25 mm aperture, with rack and pinion focus- sing; on steel pillar, and adjustable, for reading barometers and air thermometers, scale and \cinici <>l dcrmaa silver Tin- instrument has a range of 90 cm ; the vernier gives direct 0. 1 mm. The .instrument is main- tained perpendicular by plummets. The telescope is provided with an inclinable level and has a fine screw-adjustment. 25. 0. 0 7. 0. 0 i I. IL1:!. :iL's;, rjl. IL'.Y No. :.I ITL'. Comparators, Reading Telescopes, Screw Micrometers. 225 51469. 51470. 1 : 7. 51 472 A. 1:5. 51 472 B. 1:5. 51471. 1 : 4. 51.467. Comparator ior rules divided with lines Lengths up to 1 m can be compared with this instrument. It consists of an iron bench, and two reading microscopes can be moved along the entire length of this bench, being also capable of lateral motion. The microscopes have micrometer eyepieces with movable line. If desired, Fraunhofer micro- meters are supplied at a proportionate increase in price. 51.468. Apparatus for Calibrating and Testing Thermometers (Comparator), Figure. . . Two micrometrically adjustable reading microscopes can be moved along the length of a hori- zontal rail. 51.469. Reading Telescope, on stand, Figure, rack and pinion focussing; objective 25 mm aperture and 200 mm focal length, with two magnifications Xl2 and x24, astronomical; quite free from iron parts so as to enable galvanometrical and magnetometrical read- ings to be made with it 51.470. Simple Reading Telescope, Figure, with objective 24 mm in diameter and cross lines, with horizontal and vertical rotation, and vertical adjustment 51.471. Screw Micrometer (Fraunhofer's), Figure, measuring accurately 30 mm to Vsoo mm; with low power microscope capable of rotation about a horizontal axis and sliding on a pillar, so that measurements can be made in any direction 51.472. Screw Micrometer (Fraunhofer's), Figs. A and B, on a folding stand, for vertical and horizontal observations; can also be used as a microscope with detachable and sliding microscope table. Price, in box £ s. d. 47.10.0 17.10.0 5.10.0 1.15.0 14. 0.0 37.10.0 Reading Telescopes for Mirror-Reading see section: "Electricity". d. iL'i;. .v,;iL'. 42!), 4:ili, 4L-X. 15 226 Measuring of Lengths, Angles, etc. No. :.l 473 — ;!;-i!il^; 51473. 1 : 5. 51474. 1:4. 51475. 1 : 3. 51 476 A. 1:2. 51 476 B, 51477. 1:2. 51.1 7.'5. Large Reading Microscope, on stand with levelling screws, with 3 oculars, Figure The microscope can be raised and lowered, rotated and moved by means of fine adjustment < The measuring graduations within the limits of about 20 mm are effected by a horizontal and vertical motion. The objective is illuminated by a glass plate inclined at an angle of 45°. 51,474. Reading Microscope, Figure, with extension and rack work for adjusting at heights of from .34(1 to 550 mm, draw tube and prism are graduated; vernier residing t<> ' ,„ mm; rotary in horizontal plane; with level, double objective for the 3 widths of objective 50, 90 and 480 mm, eyepiece and micrometer eyepiece 6. 0. £ s. (1. 19. 0. 0 5l.l 75. Reading Microscope for Thermometer Degrees, as suggested by Nansen, Figure The microscope holder has a sprint; damping arrangement for fixinj; thermometers of various thicknesses. The microscope has a micrometer eyepiece and a magnification of x 12. :?. o. o cl. 1:11. 4:«. i::i, IX,, No. M IM. Reading Microscopes, Longitudinal Dividing Engines. 227 51478. 1:8. 51 480. 1 : 7. 51.476. Reading Device for Thermometers, Burettes, etc. from 6 — 20 mm diameter, Figs. A and B, comprising stand with locking frame, mirror inserted for mirror readings and glow lamp inserted for illuminating The glow lamp is supplied for 2, 4 or 6 volts; if voltage is not stated when ordering, a 4 volt lamp is supplied. 51.477. Magnifying Glass with Cross Wires, for high magnification (cf. Fig. 51,476 B) . . 51.478. Dividing Engine for lengths to 500 mm, carefully and massively constructed, Figure, with screw of 1 mm pitch, arrangement on the drawing mechanism for drawing the 5ths and 10lh8 longer, and with reading microscope The illustration does not now represent the drawing mechanism, this having been considerably improved. 51.479. - - idem, without reading microscope 51.480. Longitudinal Dividing Engine for fine and coarse graduation, Figure, for lengths to 350 mm, total length of machine 850 mm (Fr. phys. Techn. I, 1, Fig. 1963) . . This machine divides accurately to l/la> mm by means of a dividing wheel and a screw with milli- metre pitch; the drawing mechanism rests firmly on the powerful cheeks and permits of the mechanical drawing of graduations of various lengths. For reading microscope for this engine, see No. 51,481. 51.481. Reading Microscope with adjustable wires, on a slider fitting the machine . Each £ s. d. 0.13.0 0. 8.0 25. 0.0 22.10.0 32.10.0 7.10.0 Cl. 3773, 3623. 15" 228 Measuring of Lengths, Angles, etc. N". M HL' 51482. 1:10. 51484. 1 : 6. 51485. 1:6. 51 486. 1 : 4,5. 51.482. Dividing Engine, Figure, 0.75 m long, of polished oak, with adjustable, iron arm and female scale holder, iron runner, rails which can be conveniently adjusted as regards height and sliders which may be firmly clamped, unscrewable bow, device for ob- taining graduations of varying lengths, and with sliding drawing mechanism having triple arresting device (Fr. phys. Techn. I, 1, Fig. 1959), without female scale . . . This machine is specially intended for glass and thermometer scales, also for simple scales on wood, glass or opal glass. 51.483. Female Scale for above, with 360 divisions of each 2 mm on one and 180 divisions of each 4 mm on the other side 51.484. Circle Dividing Engine, Figure, with plate 250 mm diameter, graduated on silver in V*0 and graduations for the verniers, tangential screw and dividing drum, with Micro- scope (Chwolson, Physik, Vol. I, Fig. 131) 51,485. Circle Dividing Engine, Figure, similar in construction to preceding, with plate 300 mm diameter, graduated on brass, without microscope (Fr. phys. Techn. I, 1, Fig. 1970) ' The circle is divided into 720 parts and has a tangent screw; one complete turn of this cone sponds to '/t*- £ s. d. 8. 5.0 1. 4.0 40. 0.0 48.15.0 f>l.4X(». Microscope for Circle Dividing Machine Xo. 51,485, Figure 3 15 0 fil,4s7. Small Circle Dividing Engine, for rapidly making graduations for which to an accuracy is not necessary o great 25 0 0 Tin- brass plate, 250mm in diameter, has a point-alidade of 3(>o and lini points bored to be firmly held in any position. * 51,488. Circular Vernier Model, Figure, for the projection lantern in so as 1 5 (1 M.1S9. Circular Vernier Model (\V. & K. phys. I'rakt.. Fig. 11. — (Ian. -Man. Fisr. 66), of wood of 80 cm radius, giving 1 minute of arc, el'. Fig. 51,490 sextant 1 4 0 * fan be used with projection lantern < 1. 412. 444. 41.-.. :,4*' X.i. :.l I'.i-J. Dividing Engines, Circular Vernier Models, Goniometers. 229 51488. 1:3. 51490. 1 : 7. 51492. 2: 3. 51493. 2: 3. 51491. 1 : 8. 51 498. 1 : 6. 51.490. Circular Vernier Model, small pattern, sextant of 40 cm radius, giving 2 minutes £ »• d. of arc, Figure 1. 0. 0 51.491. Wood Protractor on Stand, Figure (F. C. G. Miiller's), with plumb bob (M. T., Figs. 6, 14, 15), for angular measurements in mechanics and optics 2. 10. 0 51.492. Plumb Bob, brass, Figure, with steel tip. for unscrewing 0. 2. 6 51.493. Plumb Bob with Spirit Level, Figure, of brass, with steel tip for unscrewing . 0. 5. 0 51.494. Simple Gnomon, for class use (Noack, Leitfaden, Fig. 6) 0. 13. 6 51.495. Surface Goniometer with fixed limbs, circle divided in 1/2 degrees, surface bar of steel, radius of circle 70 mm, in case, Figure 1. 16. 0 51.496. -- idem, smaller, Figure, with detachable limbs, in case, 80 mm diameter . 1.12.0 51,496 a. - - i d e m, limbs undetachable i 1. 0. 0 51.497. Field Goniometer (Ohmann's), for class use (Ztschr. f. d. phys. u. chem. U., 5, 1892, p. 166) 1. 15. 0 51.498. Plumb Line, Figure 0. 5. 0 For spirit and other Levels, see section " ™f S ^''' ^"' Equilibrium, etc. of Liquids. i.!^ uti. 230 Measuring of Lengths, Angles, etc. No. 51 49fl - 51504. 1 : 10. 51.499. Model of a Mirror Reading (W. & E. phys. Prakt., Fig. 19), Figure, for sub- jective and objective reading 51.500. Planimeter (Amsler's), Figure, arranged for a vernier unit between 8 and 10 sq. mm, as desired, with check ruler, in case . The pole arm is 19 cm long, the travelling rod 16 cm. 51.501. - - idem, with micrometer and vernier on the travelling rod, for any values of the vernier unit from 2 to 10 sq. mm, adjusted for 4 vernier units 51.502. - - idem, with correction for parallel position of the roller axis and of the travel- ling rod 51.503. Slide Rule with Instructions (M. T., p. 24), 27 cm long, readings accurate to 3 places This slide rule is arranged for rapidly multiplying, dividing, squaring, cubing, obtaining square and cube roots, for obtaining logarithms and numbers, sines and tangents. The slide rule is also used as a scale for drawings and as a longitudinal rule for lengths up to 50 om. 51.504. Demonstration Slide Rule, Figure, 21/2 m long, without stand, graduations 8 times as long as in rule No. 51,503 .".1.505. -- idem, with stand (Fr. phys. Techn., Vol. I, 2, Fig. 2030) 51.506. Litre Vessel, cube shape, with black and white graduations in square centimetres (M. T., p. 23; also see Meyer, Naturlehre, p. 7). The wood cube No. 51,514 fits this 51.507. -- idem, cylindrical (Meyer, Naturlehre, p. 7) 515 50S. Hollow Cube of thick sheet brass, volume 1 litre exactly, with white and black gra- duation in square centimetres on two sides 51.50!) Hollow Cube of 3 cm length of side (W. D., p. 60 [54]), for reducing the gramme weight to the metric measure 51.510. Vessel of 1 Cubic Inch, of brass, cuneiform 51.511. Metal Cube with Hollow Cube of 1 cm side, fitting one in the other 51.512. --idem, 2 cm side 51.513. --idem, 3 cm side 5J,514. Cubic Decimetre of Wood, cube shape, fitting the litre vessel No. 51,500 (Meyer, Naturlehre, p. 7) ci. HI;. i:i!i. 5602. No. .MM' I. Balances and Sets of Weights. Analytical Balances. 231 C5 51519. 1:6. 51523. 1:6. Balances and Sets of Weights. o I Analytical Balance, with short-arm triangular Aluminium Beam and rapid-oscillation pointer, F i g. 51,519, best nickelled brass pillar, with arrestment for beam and suspension, also a device for shifting the rider when the case is closed. The balance has agate bearings, gilt or platinised pans; the case is of dull, nickelled brass and glass, the balance rests on a dead-black plate glass base with levelling screws; it has 4 aluminium and glass sliding windows. A level is given in. The balance is very compact and very neat in appearance. 51,517 51,518 51,519 5 50 200 0.02 0.05 0.1 10. 10. 0 13. 0. 0 16. 0. 0 £ s. d. List No. To carry Sensitivity Price with gilt steel axes £ 51,520 1000 grams 0.2 mg 19. 10. 0 Prices without Rider Weights. For Sets of Weights and Rider Weights, see pp. 241—243. Without the lateral Rider Arrangement the prices of these balances are reduced by 5 s. Analytical Balance with short-arm triangular Aluminium Beam and rapid-oscillation pointer, Figure, with round, best nickelled brass pillar, with arrestment for the beam and suspensions, also arrangement for shifting the rider without opening the case. The balance has agate bearings, gilt or platinised pans, finely polished case of mahogany and glass, with 2 glass sliding windows and 2 side doors; resting on dead-black plate glass base with levelling screws and a level. List No. 51,521 51,522 51,523 To carry 5 50 200 Sensitivity 0.02 0,05 0.1 Price with gilt steel axes £ 7. 15. 0 9. 0. 0 11. 0. 0 51,524 1000 grams 0.2 mg 13. 5. 0 Prices without Rider Weights. For Sets of Weights and Rider Weights, see pp. 241—243. If without the lateral Rider Arrangement these balances are reduced in price by 5 s. Cl. :>4'JG, 5494. 232 Balances and Sets of Weights. No. r>i :.L'.-. 51526. 1:6 51 528. 1 : 3. 51,527 1000 grams 0.5 mg 12.0.0 Analytical Balance, with half-length Beam, Figure 51,526, with adjustable end knife edges; round, best lacquered or nickelled brass pillar; with arrestment for the beam and suspensions, by means of which the centre and end knife edges can be removed from the bearing; and with arrangement for shifting the rider and brush device for arresting the pans. The bearings are of agate. The glass case has a walnut frame, a sliding door in front balanced by counterpoises, and side doors. The case is finely polished, the cornices and projecting ornamental parts being polished black. Levelling screws and level are supplied. List No. 51,525 51,526 To carry 50 200 Sensitivity 0.1 0.1 Price, lacquered or nickelled, with gilt axes £ 8. 15. 0 10. 10. 0 Prices without rider weights. For Sets of Weights, see pp. 241—243. The rider glide of this balance is arranged for the entire length of the beam. The two halves of the beam are divided into 100 parts. The balance is so adjusted that its sensitivity when the maximum load is applied is the same as when unloaded. These balances are also, if desired, supplied with mahogany cases instead of walnut cases, with- out extra price. x r>l,.~iL'S. Micro-Balance, Nernst's, Figure, a torsion balance for weights to 2 milligrams and for an accuracy of Vioon to ''/„»,„ milligrams. (Berichte der Deutschen Chemischen Gesellschaft, 36, No. 10, and 38, No. 1. - - Fr. physik. Techn. I, 2, Fig. 2251) . . . Short Triangular Beam Analytical Balance, of lacquered brass, quick-swinging type, with pointer suitable for rapid work; plane, firm centre bearing. The pans are nickelled. The balance has a black enamelled iron pillar with plummet. The arrestment of the compensating suspenders moves in the are of oscillation of the beam. The rider scale rests iii the axial plane and is divided on both sides into 100 parts. The glass case, resting on a dead-black plate glass slab, is fitted with levelling screws, and has a sliding \\iudo\v in front balanced by counterpoises. Figure 51,529. List No. 51,529 To carry 200 Sensitivity 0.2 Price £ 6. 10. 0 51,530 50(1 grains 0.5 mg 7.10.0 SO o |» C I I a p 5. 10. 0 Cl. 549:i. No. :,1 .VI!). Analytical Balances. Precision Balances. 233 51 529. 1 : 6. 51533 (51537), 51578. 1 : 8. Analytical Balance, also suitable for specific gravity determinations, cf. Fig. 51,533, with agate planes, gilt or platinised pans, mahogany-glass case with 4 sliding windows, alu- minium beam with quick-swing pointer, on white or black plate glass base, with rider slide when case is closed. The following are not included in the price: the stage, the glass vessel, the Eeimann thermometer flask, the rider weights and counterpoises. £ s. d. List No. 51,531 51,532 51,533 51,534 To carry 5 50 200 1000 grams Sensitivity 0.1 0.1 0.2 1 mg Price £ 5. 15. 0 6. 10. 0 7. 15. 0 10. 5. 0 Prices exclusive of Rider Weights. For Sets of Weights and Rider Weights, see pp. 241—243. The preceding, without iron or steel parts, agate axes. List No. To carry Sensitivity Price £ 51,535 5 0.1 6.5.0 51,536 51,537 51,538 50 200 1000 grams 0.1 0.2 1 mg 7.0.0 8. 10. 0 11. 0. 0 51,539. Precision Balance for Rapid Work, Figure on p. 234, for load of 200 g, with lens- mirror reading and two superposed scales, case with sliding windows and side doors, axes and bearings of best agate, mounted on marble slab In order to read the tenth-milligrams direct with this quick-swing balance, a power 5 lens-mirror (achromatic objective with silver coating) is fixed on the pillar and magnifies, without reflex or distor- tion, the whole of an opal glass scale, divided in V.-,'118 mm, fitted about 20 mm above the ivory scale. The whole milligrams are read off on the ivory scale; the tenth-milligrams being determined by glancing at the glass scale on the mirror for purposes of confirmation. As therefore the mirror and the magnification which is read by both eyes is only used at the last moment, the eyes are not in any way strained. The work with both scales is excellent, sure and rapid. The deflection with all loads is, in the mirror, 10° and on the ivory scale 2° per milligram. Extra if mounted on glass slab If Microscope Reading is fitted in place of the mirror the balance is increased in cost by . . 9. 10. 0 0. 5. 0 1. 5. 0 Cl. 5495, 3939. 234 Balances and Sets of Weights. No. M .Mil 51539. 1:6. 51548. 1 : 8. 51556. 1 : 8. 51,541 200 4. 0.0 4. 10. 0 51,542 500 4. 5.0 4. 15. 0 51,543 1000 4. 15. 0 5. 5.0 51,544 5000 8.5.0 9.0.0 Precision Balance for Chemical and Physical Purposes, see Fig. 51,542, high sensitivity, also arranged as a hydrostatic balance, with beam and pan arrestments; glass case with balanced front sliding window. The price does not include the auxiliary parts illustrated, see No. 51,545. List No. 51,540 To carry 100 (a) On Board £ 3. 10. 0 (b) On base with levelling screws £ 4. 0. 0 51,545. Auxiliary Parts to Balances Nos. 51,540 — 51,544: Tripod, Glass Jar, Plummet and Thermometer Chemico-Technical Balance, F i g. 51,548, in polished, glazed walnut case with front sliding window (which may be fixed in any position) and with levelling screws. List No. 51,546 51,547 51,548 51,549 51,550 51,551 To carry 20 50 100 200 500 1000 grams Sensitivity 111225 mg Price £ 2. 0. 0 2. 5. 0 2. 10. 0 2. 15. 0 3. 5. 0 3. 15. 0 1. 0. 0 Cl. till. 194. :IL'I No. 51566. Precision Balances. Chemico-Technical Balances. 235 51 560 a. 1:8. 51 561 b. 1:8. Precision Balances for technical purposes, Figs. 51 552 and 51,556. £ s. d. To carry grams Sensitivity mg Lacked { On Iron Base 100 250 2 3 51,552 51,553 1. 18. 0 2. 2. 0 On Wood Box 100 250 2 3 51,554 51,555 2. 0. 0 2. 5. 0 In Glass Case with levelling screws, plum- met and rider slide 100 250 1 2 51,556 51,557 3. 15. 0 4. 5. 0 The balances in glass cases can, if desired, be adjusted to be still more sensitive than here mentioned. Chemico-Technical Precision Balance, with aluminium beam and brass stand (short beam), with arrestments for beam and suspenders, brush pan-stops, Figs. 51,560 a and 51,561 b. List No. 51,558 51,559 51,560 51,561 To carry 5 50 200 1000 grams Sensitivity 1 2 4 10 mg (a) In Glass Case £ 2. 12. 0 3. 5. 0 4. 0. 0 5. 5. 0 (b) On Box, with moulding . £ 2. 5. 0 2. 12. 0 3. 5. 0 4. 2. 0 (c) On Board £ 1. 16. 0 2. 4. 0 2. 15. 0 3. 10. 0 Precision Balance for heavier Loads, with short aluminium beam, arrestments for beam and suspender, brush pan-stops. List No. 51,562 51,563 51,564 51,565 51,566 To carry 1 3 5 10 20 kg Sensitivity 10 20 30 50 100 mg (a) In Glass Case .... £ 4. 15. 0 6. 0. 0 7. 10. 0 9. 10. 0 12. 0. 0 (b) On Box, with cornice . £ 3. 12. 0 4. 6. 0 5. 10. 0 7. 5. 0 9. 10. 0 (c) On Board £ 3. 0. 0 3. 12. 0 4. 15. 0 6. 5. 0 8. 5. 0 Cl. 32(14 I. 5498, D499. 236 Balances and Sets of Weights. No. r.l :.i;7 51 569. 1 : 8. 51567. 1 : 6. 51573. 1 : 9. 51 571. 1 : 5. 51.567. Precision Tare Balance (Mach's), for rapid work, Figure, nickelled, with side doors, on black plate glass base (Chemiker-Ztg. 25, 1901, p. 1139, and 27, 1903, p. 249) The balance is set up so that the balance-beam is turned towards the viewer, the one weighing pan being accessible for both hands. This balance is very convenient, especially when a large series of samples of the same weight have to be weighed and the weight has not often to be changed. If specially desired, the balance is also supplied set up in the ordinary manner. 51.568. Set of Weights for above, 500, 200, 100, 50 grams, for placing inside the case . . Mohr's Pillar Tare Balance, Figure 51,569, beam working in the pillar, sensitivity 50 ing for 1 kg load; constructed entirely of brass. List No. 51,569 51,570 To carry 0.5 1 (a) Without box or base .... £ 1. 5. 0 1. 8. 0 (b) Polished box with 2 drawers £ 0. 11. 0 0. 11. 0 Tare Balance, Figure 51,571, with pierced gunmetal beam, prismatic axes, resting on 3 agate planes, with elegant brass pillar; the pointer plays on an ivory scale. List No. 51,571 51,572 To carry 1 3 kg On Mahogany box with 2 drawers £ 2. 5. 0 2. 10. 0 51,573. Single Arm Balance ( \\Vst pual's) for specific gravity determinations, Figure, with adjustable, lacquered brass stand With this balance the specific gravity of liquids can be determined to 4 \>\: s of .l.vimaK The followiii}: pertain l«> the balance: 1 glass plummet, 1 Koimann flask with tlicnimmrtrr stopper, 1 counterpoise, 8 ridcre, 1 pair forceps and 2 platinum wires, cii.se and instructions. £ 6. s. d. 0. 0 0. 18. 0 1. 6. 0 M, 3>7. 7:,7. L>l«i. No. .-,l.-iso. Precision Balances, Tare Balances, Specific Gravity Balances. 237 51 576. 1 : 6. 51 578. 1 : 5. 51.574. Specific Gravity Balance (Mohr's), Figure, with arrestable stand and pans for ordinary weighings, of lacquered brass with accessories illustrated This balarce serves for determining the specific gravity of liquids and solids to 4 decimal places. All parts can be placed in the lock-up drawer of the support. 51.575. - - idem, with nickelled brass parts 51.576. Specific Gravity Balance, Figure, both arms graduated, with adjustable stand with support and with spring arrestment, the latter being actuated by lightly pressing the knob a. The central bearing and arrestment are of agate. The lock-up drawer is arranged to take the entire balance and the lower base has levelling screws. Price, including accessories illustrated, balance lacquered 51.577. - - idem, the balance nickelled 51.578. Outfit for Specific Gravity Determinations on liquids and solids, for analytical balances Nos. 51,519, 51,520 and 51,523, 51,524, Figure, owing to the height of the pans this outfit can only be used for the balances to carry 200 grams and 1 kg 1 Reimann Thermometer, 15 g weight, displaces 5 g distilled water at 15° C. (4 S. 3d.), 1 ad- justable stage for the glass jar (M. T., p. 103 [3 S.]), 1 counterpoise each of 10 and 5 grams each 6 d. (1 S.), 1 glass plummet (9 d.). 51.579. Hydrometer (Eeimann's), Figs. A and B, for determining the specific gravity of liquids, with a 1-gram patent body and a pan for use as substitution balance, resting in polished box, with 2 glass jars 5.1 ,580. --idem, in glass case • £ s. d. 1.15. 0 1.18. 0 2. 0. 0 2. 3. 0 0. 9. 0 1.10. 0 2. 5. 0 Cl. 200, 198, 199, 5497, ;,4'.IL'. 238 Balances and Sets of Weights. 51 586. 1 : 10. 51 588. 1 : k- Jf cm: 51 589. 1 : 8. Hydrostatic Balance, Figure 51,582. £ s. d. List No. 51,581 51,588 51,583 To carry 1 2 5 kg Sensitivity 10 20 50 mg Price £ 3. 10. 0 4. 0. 0 5. 0. 0 Gunmetal Beam working on brass pillar, with beam arrestment, on mahogany board with two long and one short brass pans and adjustable plate stand. Axes working on stones. Hydrostatic Balance, sufficient where demands are not great, Fig. 51,586. List No. 51,584 51,585 51,586 51,587 To carry 100 250 500 1000 grams Price £ 0. 13. 6 0. 14. 6 0. 17. 0 1. 0. 0 51.588. Hydrostatic Balance, to carry 250 grams, Figure, with beam adjustable in an up-and-down direction, 2 pans with long stirrup and 1 pan with short stirrup, brass body, jar and plummet (for explaining the Archimedian principle) and with set of weights from 1 mg to 200 grams. The balance indicates 5 mg ! 1. 10. 0 51.589. - - idem, without above-named accessories, Figure, with 3 pans 1. 0. 0 :• l .590. Demonstration and Hydrostatic Balance, Figure, with 2 weights of 200 g and 1 weight of 100 g, also 2 long and 2 short pans 6. 10. 0 The balance is 60 cm high, fitted with rigid pillar and is very sensitive for its size, The de- flections are large and can be read from a distance. The balance permits of explaining: distribution of the lever — shifting of centre of gravity - im-rea.se and decrease of sensitivity on lengthening and shortening the lever — results of placing the suspension axes above or below the central axis — testing the balance for proportionality — adjustim: the inequality of arms — correct weighing with an unequal arm balance — determining the error of the lever — use of balance for determining the specific gravity of solids and liquids. The balance can in addition be used as a tare balance for loads to 1 kg. 51.591. 1 Case iii which to lay and despatch the balance No. 51,590 1. 5. 0 .M.592. Arrangement for Hydrostatic Tests, Figure, for raising and lowering the glass i •li;mir;ill\ 1. (I. (I :.l.. "»!i.'>. Large Demonstration and Hydrostatic Balance, Figure The balance in l.Kl in high ami lias a sensitivity of 10 mg on each side \\ith its maximum load nf ."> kg. thus rendering it suitable for use a.s an ordinary balance. The balance lias excentric arrestment. rider scale and two pairs of pans of different sizes; as the suspenders are exactly equal the smaller pans can be suspended instead nf (he larger. 10. 0. 0 ci. i. 3793. No. M .v.i I. Demonstration and Hydrostatic Balances. 239 51590. 1:5. 51593. 1:11. 51 592. 1 : 5. 51594. 1 The beam has two pointers and the pillar two scales, one of each of these facing the lecturer £ s. d. and the other the audience. The following instructive experiments, amongst others, may be carried out with the balance: (a) Equal and unequal arm balance with long pointer; (b) Weighing with the rider scale; (c) Equal arm balance with short pointer; (d) Lengthening a lever arm; (e) Shifting the line of axis above or below; (f) Hydrostatic balance. Outfit for Hydrostatic Experiments : see No. 51,592. 51,594. New Demonstration Balance (Buff's) (W. & E. phys. Prakt., Fig. 29) ...... 2. 10. 0 (1) The knife edges carrying the pans can be brought into the same plane as the central knife edge or be removed from the latter. (2) The centre of gravity of the beam can be displaced, and (3) the length of the arms of the beam can be varied. ci. ;..•>.').•!. 211. 210, 3791. 240 Balances and Sets of Weights. 51597 — 51600. 1:10. 51 595. 1 : 10. 51.595. Chemical and Hydrostatic Demonstration Balance (Sehwedoff's), Figure (Ztschr. f. d. phys. 11. chem. U. 16, 1903, p. 321. - - Frick, Phys. Techn. II, 1, Fig. 2128) . . In order to obviate the tedious selection of suitable small weights and the inconvenience of laying the rider on the beam during the lecture, and to facilitate reading from a distance, a spring pointer is firmly fixed to the beam of the balance, this pointer being arranged in front of a semi-circular scale. In using the balance the weight to be determined is first obtained roughly by adding tare weights to the pan; the fine pointer is then guided by hand over the scale, this motion causing a small knob, fixed in front, to move in the corresponding direction until the beam has reached the state of equilibrium. In this position the fine pointer shows the fractions. With the aid of the arresting fork it is possible to support both arms of the beam at once or each separately. 51.596. Weighing Pan for hydrostatic experiments, for preceding balance 51.597. Demonstration Indicating Balance (Hartl's), Figure, suitable for a large number of experiments in statics, mechanics and electro-mechanics (Ztschr. f. d. phys. u. chem. U. 10, p. 127), for 250 and 500 grams range, without accessories The balance is used for measurement experiments as to adhesion and cohesion of liquids, fric- tion, stability, magnetic attraction, etc.; also for demonstrating Archimedes' principle and for deter- mining the density of solids and liquids. 51.598. Simple Accessories for Balance No. 51.597: 1 adhesion plate (glass), 1 tribometer with slider, 1 glass jar and 1 glass flask, connected together by rubber tubing; 1 plunger, 1 holder with wire clamp, 1 massive iron cylinder (see Figure) 51.599. Further Accessories for Balance No. 51,597: 1 floater, 1 glass jar with syphon, 1 beaker, 1 hollow cylinder, 1 solid cylinder, 1 sheet metal plate, 1 wood block (cf. Ztschr. f. d. phys. u. chem. I". 8, p. 207); in addition, for experiments on the dependence of wind pressure on the shape of the impressed surface and the dependence of the resistance <>!' a liquid against the motion of a solid in the same on the velocity and the shape of the impact surface of the body: 1 hollow brass cone, 1 hollow brass sphere. 1 base support. There is also eomprised in the accessories 1 measuring flask (pycnometer) for determining the density of pulverulent bodies (see Figure) 3. 0. 0 51.600. Solenoid on Stand, with soft iron core and hollow iron cylinder, for experiments on magnetic attraction. Accessory for balance No. 51,597, see. Figure .M.iiOl. Plane Plate and Hollow Hemisphere for impact experiments with liquids (M. 1., 71 and p. 109) .............................. 0. 3. 0 ."il.tio:;. Table for Hydrostatic Balances, \\itli serpentine base, Figure ......... JO. 3. 0 '• Cl. 3285, 3266. No. .',1 liL'7 Balances and Weights. 241 51614. 1:10. 51 619. ; S. 51 609. 1 : 8. 51 624. 3 : 10. 51.604. Large Letter and Sorting Balance (German "rapid" balance), Figure, accurately divided to 500 grams, compactly constructed for demonstrations and weighings in rapid succession (Fr. phys. Techn., I, 2, Fig. 2122) The manufacture of indicating balances is carried on as a spesial branch of our trade, and we supply these as per special price list, especially for the textile and paper trades. 51.605. Bridge Balance for 200 kg carrying capacity (M. T., p. 28), of oak Hand Balance with round horn pans, Figure 51,609. 51,606 51,607 51,608 51,609 10 13 17 22 5 20 50 200 0. 2. 6. 0. 3. 3 0. 4. 0 0. 5. 0 List No. Length of beam cm To carry Price £ 51,610 51,611 30 35 500 1000 gr 0.8.6 0. 12. 0 51,617 51,618 20 25 kg 1.5.0 1. 10. 0 Flat Balance, Beranger system, Figure 51,614 (M. T., p. 28). List No. 51,612 51,613 51,614 51,615 51,616 To carry 1 3 5 10 15 Price £ 0. 11. 0 0. 12. 0 0. 13. 0 0. 15. 0 1. 0. 0. Table Balance with Jockey Weight, Figure 51,619, with tare weigh-pan. List No. 51,619 51,620 Scale divided every 10 gr to 20 25 kg Size of slab mm 230x350 250x400 Price £ 2. 5. 0 2. 10. 0 The small pan to the right serves for calculating the tare of vessels and the like which have not to be weighed in with the contents. Analytical Weights for Chemico- technical and Physical Purposes, accurately adjusted among each other, Figure 51,624. 51,626 500 1001 51,622 20 51,623 50 51,624 100 51,625 200 51 101 201 501 1.0.0 1.3.0 1.8.0 1. 17. 0 List No. 51,621 From 1 mg to 10 Comprising altogether 31 Price per Set £ 0. 18. 0 1. 0. 0 1. 3. 0 1. 8. 0 1. 17. 0 2. 7. 0 The weights, with ivory forceps, are contained in a neat mahogany box; in the sizes down to 1 gram they have small knobs screwed in; they are made of brass, gilt and are each inserted in velvet. The fractional gram weights from 500 to 10 mg are placed under a thick glass cover. The sets Nos. 51,621 to 51,627 can also be supplied at the same price platinised instead of gilt. 51,627 1000 gr 2001 gr 2. 19. 0 £ s. d. 1.16. 0 2. 0. 0 Spring Balances, Pression and Tension Dynamometers: see Mechanics (Elasticity). Balance Brackets: see page 41, No. 50,267. Cl. 3241, I I.V.I.:, 1*7. 4082, 5490, 213. 1 Q 242 Balances and Sets of Weights. No. 51 51635. 3:10. 51 631. 3 : 10. 51636 odor 51645. 1:3. 51 637. 1 : 3. 51638. 1:4. Analytical Weights, somewhat simpler construction, accurately calibrated, Figure 51,631. List No. 51,628 51,629 51,630 51,631 51,632 51,633 51,634 From 1 gr to 10 20 50 100 200 500 1000 gr Comprising together 31 51 101 201 501 1001 2001 gr Price per Set £ 0. 12. 0 0. 13. 6 0. 15. 0 0. 17. 0 1. 3. 0 1. 9. 0 1. 18. 0 The weights, together with brass forceps are contained in a polished mahogany case; in sizes to 1 gram they are made of brass with heads screwed in and are gilt; the fractional grammes, of German silver, are under glass. We also supply sets Nos. 51,628 — 51,634 at the same price platinised instead of gilt. 51.635. Analytical Fractional Gram Weights of Platinum and Aluminium, from 1 gram to 500 mg, 0.1 and 0.01 mg in duplicate, 0.001 mg in triplicate, in elegant mahogany case with stout glass lid, each lying in separate frame, Figure, 0.5 to 0.01 mg weights of platinum, 5, 2 and 1 mg of aluminium. Per set 51.636. Analytical Fractional Gram Weights, of platinum, from 1 mg to 500 mg, in mahogany case with lid and forceps, Figure 51.637. Rider Weights, Figure, of aluminium, in dull walnut case with forceps, con- taining 9 aluminium riders from 10 to 500 mg, for the rider slides of the analytical balances Nos. 51,517 — 51,527, 51,529—51,534. The rider weights can easily be recog- nised one from the other by the number of the rings; the 10 and 100 mg have each one ring underneath on each side; the 20 and 200 mg have each two rings, and the 50 and 500 mg each 5 rings. Case with 9 riders and forceps s. d. 0.11. 0 0. 12. o 0. 5. 6 51,638. Precision Weights, Check Standards, with No. I extra fine calibration, in polished mahogany case with forceps, Figure, going from 1 mg to 200 grams, all "twos" in duplicate, containing altogether 611 grams. The gram weights are gilt, and the fractional grams arc of (lerinan silver, under glass 0.16.6 Precision Weights, extra-fine calibration I, in polished pear-wood box with forceps, the grains being of phosphor bronze, the fractions of German silver, under glass, all the "twos" being in duplicate. Figure 51,643. List No. 51,639 51,640 51,641 51,642 51,643 51,644 1 mg to L'O 50 100 L'uo 500 1000 gr Price per Set £ 0. 7. 0 0. 8. 6 0. 10. 0 0. 15. 6 1. 0. 0 1. 8. 0 Cl. 214, 215. 216, 5491, U'17. Xo. 51667. Precision Weights. 243 51643. 1:4. 51 649. 3 : 10. 51655. 3:10. 51662. 3:10. 51 666. 1 : 4. 51,645. Precision Fractional Gram Weights, extra-fine calibration I, from Ifmg^to 500 grams; 5, 2 and 1 mg of aluminium, the remainder of pure nickel, in mahogany case with lid and forceps, Figure on p. 242 Precision Weights, with fine calibration II, Figure 51,649, in polished beech box, with forceps, of nickelled brass, the fractions of German silver, under glass ; containing 100, 10, 2, 0.1, 0.01 g in duplicate; the 100 gram set has only one 100 gram weight. List No. 51,646 51,647 51,648 51,649 51,650 51,651 10 mg to 20 50 100 200 500 1000 grams Price per Set £ 0. 4. 6 0. 5. 0 0. 6. 0 0. 9. 0 0. 12. 0 0. 17. 0 Precision Weights, with fine calibration II, in polished beech block case, with forceps, of brass, nickelled, the fractional grams of German silver, without glass. The 100, 10, 2, 0.1 grams are in duplicate. Figure 51,655. List No. 51,652 51,653 51,654 51,655 51,656 51,657 100 mg to 20 50 100 200 500 1000 grams Price per Set £ 0. 3. 6 0. 4. 6 0. 5. 6 0. 8. 0 0. 11. 6 0. 16. 6 Precision Weights, with No. Ill calibration, in polished beech block box, of nickelled brass, the 100, 10 and 2 grams being in duplicate. Figure 51,662. List No. 51,658 51,659 51,660 51,661 51,662 51,663 1 g to 20 50 100 200 500 1000 grams Price per Set £ 0. 2. 6 0. 3. 0 0. 4. 0 0. 6. 0 0. 8. 6 0. 13. 0 Precision Weights, with No. Ill calibration, in sliding box with forceps, nickelled, the "twos" being in duplicate, Figure 51,666. List No. 51,664 51,665 51,666 51,667 1 mg to 1 2 5 10 grams Price per Set £ 0. 2. 0 0. 2. 3 0. 2. 6 0. 2. 9 Cl. 218, 219, 220. 221, 222. 16* 8. d. 0. 5. 6 244 Balances and Sets of Weights. Measurement of Time. No. :>i >;i;:i 51 670, 51 674. 1 : 4 51686. 1 : r,. Precision Weights, with No. Ill calibration, in polished walnut case, upholstered plush, £ * l.»;s<;. Sundial, simple form, Figure -'. 51 687. Simple Gnomon for school use (Noack, Leitfaden, Fig. 6), see No. 51,494 .... 51,688. Seconds Watch (Stop Watch or Chronoscope), Figure, keyless, "stop" and "zero" positions, indicating 1/6 seconds 51,68!). Alarm Clock, simple (M. T., Fig. 27) 5 ],<>!•<>. Alarm Clock with switch, Figure This clock is employed for breaking an electric circuit automatically after a definite time has ••lapsed. The apparatus can be used with advantage in charging accumulators and in physical and chemical work, etc. 51,678 51,679 51,680 51,681 51,682 500 g 1 kg 2 kg 5 kg 10 kg 0.0.9 0. 11. 0 0.1.4 0.2.8 0.4.5 Cl. 22:t, 2013. No. 51 697. Clocks and Pendulums. 245 51688. 1:1. 51 690. 1 : 3. 51 691. 1 : 4. 51 695. 1 : 5. 51 696. 1 : 5. £ s. d. 51.691. Alarm Clock with switch (Gocht's), Figure, for accurate setting of the minutes 1. 5. 0 After reaching the minute for which it has been set this clock gives a ring of the bell, at the same time putting out of circuit the current at its terminals. 51.692. Clock with 10-seconcl Signal, for Laboratories; the clock gives a soft signal every 10 seconds 1. 2. 0 51.693. --idem, with Half-minute Signal 1. 0. 0 51.694. --idem, with Minute Signal 0.17.6 51.695. Compensating Pendulum, on stand, Figure, with 9 brass and steel rods, swinging to V2 seconds i 2. 10. 0 51,695 a. - - i d e m, in simpler yet reliable form, with 2 zinc and 3 steel rods 1. 4. 0 51.696. Compensating Pendulum, Figure, on stand with levelling screws, swinging accu- [ rately to 1/2 second, with driving mechanism, escapement and electric contact device i 5. 0. 0 >1,697. -- idem, with dial 6. 5. 0 Cl. 466, 3130, 4983, 629, 630. 246 Measurement of Time. No. 51 OSS — 51 698. 1 : 15. 51 701. 1 : 14. 51 703. 1 : 10. 51.698. Seconds Pendulum, in Cardanic suspension, with audible seconds beat, with firm iron stand fitted with levelling screws, Figure (Fr. phys. Techn. I, 2, Fig. 3364) . . The pendulum bob is adjustable, so that this pendulum is at the same time adapted for ex- plaining the law of the pendulum. 51.699. - - idem, with electric contact device for combining with the electric dial No. 51,705 51.700. Seconds Pendulum with wall bracket 51.701. Seconds Pendulum with audible beat, with dial and projecting pointer, on iron stand with levelling screws, Figure (Fr. phys. Techn. I, 2, Fig. 3372; Gan.-Man. Fig. 61) 51.702. - - idem, with electric Seconds Contact and an electric Dial The dial is set up at a spot in the lecture room which is easily visible by all. This arrange- ment can be thoroughly recommended for larger lecture rooms. The dial can also be used as an electric secondary clock with the aid of a clock having an electric contact. 51.703. Seconds Compensating Pendulum, Figure, with 5 brass and 4 steel rods, with audible beat and electric seconds contact, on iron stand with levelling screws, and electric dial 51.704. Clock with electric Minute Contact, Figure, for use in combination with an electric Dial No. 51,705, neat construction; can also be used as a model of a clock 51.705. Electric Dial, Figures A and B The electric dial is used either with Clock No. 51,704 (having an electric minute contact) and it then serves the function of a secondary electric clock ; or with a seconds pendulum having an electric contact, being then used as an electric seconds clock in fall experiments, etc. 51.706. Regulator Clock with seconds pendulum, case of oak, with compensating (or gridiron) pendulum 6. 0.0 10. 5. 0 (1. 4IH, -111:,, 3296. No. :.l 717. Clocks. 247 51 705 A. 1:5. 51 705 B. 1:5. 51707. 1:8. We supply School Clocks with automatic electric alarm, by which the commence- ment and finish of the studies are indicated with great punctuality; there are various patterns, and prices are quoted on application. 51.707. Electric Standard Clock for Central Clock Systems, Figure, with seconds pendu- lum, capable of simultaneously operating 40 secondary clocks; driven by weights; in oak case The clock is most carefully constructed; the dial, of finely silvered brass, is accurately graduated. This clock is also supplied in more richly designed cases in all kinds of woods, both as grandfather clocks and brack 3t clocks. Further details on application. We shall be glad to supply detailed estimates for the complete installation of clocks on receipt of precise plans. 51.708. Extra Price for a Nickel-steel Compensating Pendulum 51.709. Extra Price for a Mercury Compensating Pendulum . . . 51.710. Extra Price for a Metal Compensating Pendulum 51.711. Extra Price for a Seconds Contact, so as to be able to read seconds on the secondary clocks also . 51.712. Electric Standard Clock, as No. 51,707, with mechanical striking mechanism, by which the half and whole hours can be struck on a bell at any other places Large Standard Clock for extensive Central Clock Systems, in elegant case. List No. 51,713 51,714 51,715 51,716 With 3456 points of emission Price £ 85. 0. 0 87. 10. 0 89. 0. 0 90. 0. 0 These clocks have a large and massively constructed mechanism and can also be supplied with a mercury. or metal compensating pendulum (cf. No. 51,709 and 51,710). Up to 40 secondary clocks can be connected up to each point of emission. The contacts are visible and easily accessible; they can be cleaned without influencing the going of the clock. 51,717. Small Standard Clock with 8-day going and contact mechanism, for working small electric clock systems £ s. d. 18.10.0 15. 0. 0 10. 0. 0 7. 10. 0 4. 0. 0 23. 10. 0 5. JO. 0 Cl. 5767, 2633, 2634, 2633. 248 Measurement of Time. Nil. .M 71« 51727. 1:5. 51 728 B. 1:5. 51 728 A. 1 : 5. Secondary Clock (sympathetic clock), in wood case with carved frame and shielding glass for protected rooms. List No. 51,718 51,719 51,720 51,721 51,722 51 723 51,724 Diam. of dial cm 21 24 31 40 50 64 74 Price £ 3. 0. 0 3. 5. 0 4. 0. 0 5. 0. 0 7. 10. 0 10. 0. 0 11. 10 0 The dials have a white ground and black figures, also black pointers; other patterns can be sup- plied at a proportionate increase in cost. The clocks are also supplied with carved frame at a corre- sponding extra cost. If with double dial these clocks cost up to 31 cm diameter double, and the larger ones 75 to 40% more. Prices for secondary clocks in metal cases for unprotected rooms and for the open quoted on application. 51.725. Metronome (Malzl's) with Bell, Figure, striking the 2nd, 3rd 4th and 6th beats loud 51,725 a. - - i d e m, without bell 51.726. - - idem, with bell and Electric Contact, Figure, for releasing the fall machine and marking the closing of the circuit by striking a bell 51.727. Metronome with clockwork and mercurial contact, for Beckmann's experiments, Figure 51.728. Chronoscope (Hipp's), Figures A and B This is a most accurately working instrument for determining small intervals of time. It is employed in the determination of the frequency of sounds, the velocity of free-falling bodies, the velocity of flight of shots, etc. The instrument indicates accurately to 0.001 second. The arrestment is released a\itomatically by means of two draw cords or electrically by the aid of a double relay fitted to the back. 51,720. Current Circuit Fall Trough (Kolbe's) A ball traversing a fall channel closes an electric circuit during a certain duration of time. depending on the inclination of the channel. 51,730. Spark Chronograph (Tuning Fork Chronograph), as suggested by v. Beetz, F i g u r e (Fogg. Ann., Vol. 135, 1868, p. 126) ' A tuning fork of 250 vibrations, fixed to an axis of rotation, and sliding along a prism, writes with its style upon a lacquered and sooted surface. By discharging an induction apparatus, the sparks of which pass between the point of the style ami the soot -covered The determination of time is accurate to within 0.0005 second. £ s. .1. surface, time marks will be given. "iI.T.'.l. Cylinder Chronograph, with Hipp Eegulator, Figure, length of a second 10 mm; time (it observation up to 00 minutes. Price, without precision clock or chronometer The paper-covered cylinder is actuated by a weight-driven clockwork having a Hipp regulator. 0. 15. 0 0.12.0 1.10.0 1. 5.0 20. 0.0 7. Id. (I 85. 0. 0 wo, MO No. 51738. Chronometer, Reading Machine, Chronograph. 249 51730. 1:12. 51 731. 1 : 10. 51 736. 1 : 4. 51735. 1:4. Two electro-magnets are moved along the cylinder, working two pens. One of the electro-magnets £ s. d. receives a rush of current every second from a suitable precision pendulum clock or a chronometer fitted with an electric contact, so that seconds marks are made in the form of projections on the screw line which the pen leaves behind it on the cylinder. The other electro-magnet is actuated by rushes of current, which are given off indirectly or directly by the phenomena to be registered. The registrations of the scribing magnet are immediately alongside each other and can be measured by means of a flexible millimetre rule or a reading machine. The clockwork can be wound up without interrupting work. 51.732. -- idem, length of a second 15 or 20 mm Extra Price 3. 0.0 51.733. Marine Chronometer with electric seconds contact (precision instrument) 120.0.0 51.734. Pocket Chronometer with electric seconds contact 23. 0.0 6. 0.0 51.735. Reading Machine for cylinder diagrams, Figure, for dividing into 10, 100 or 1000 parts the seconds recorded by Chronographs Nos. 51,731 and 51,732 51.736. Strip Chronograph, Figure, with spring clockwork; length of a second 10 mm; time of observation: to 17 minutes; with 2 electromagnets 23. 0.0 The record is made in the same manner as with the previous cylinder chronographs; instead of j the pencil a style can be inserted. If desired, a weight-driven clockwork arrangement can be sup- plied at an extra price of £ 2. 15.0. This clockwork is arranged to run for 30 minutes; by lengthening the Gall chain from which the weight is suspended it is possible to prolong the time of running. Extra price on application. 51.737. -- idem, with 3 Electro-magnets, for registering the duration of two phenomena 26.10.0 51.738. Carrying Case for strip chronograph No. 51,736 2.10.0 Cl. 5706, 4849, 4848, 4888. 250 Measurement of Time. - Introduction to Physics. Xo. r.1739 — 51 744. 1 : 5. 51 746. 1 : 5. 51 749. 1 : 3. 51 751. 1 : 5. 51.739. Switch for putting the chronographs in and out of circuit from a distance. £ s ll Extra Price 7. 5. o 51.740. Other lengths of seconds from 5 to 100 mm, as desired. Extra Price £ 1. 10. 0 to 8. 15. 0 51.741. Device for two different lengths of seconds Extra Price 11. 10. 0 51.742. --idem, for 3 lengths of seconds Extra Price 14. 5. 0 51.743. Reading Machine (Oppolzer's) for strip chronographs (cf. Figure 51,744), con- sisting of a system of hairs and levers forming a parallelogram 17.10.0 51.744. - - idem, with Seconds and Minutes Counter, Figure 29. 0. 0 51.745. Reading Glass with finely diverging lines, in case 2. 0. 0 Introduction to Physics. 51.746. Displacing Cylinder for determining the Specific Gravity, Figure, with lateral £ s ''• eduction pipe (W. D., Fig. 57 [52]) 0. 5. n 51.747. Displacing Vessel (F. C. G. Muller's) (M. T., Fig. 68) 0. 6. 0 :»!.74«. Overflow Vessel (Grimsehl's) for volume determinations 0.1.0 51,749. Pycnometer, Figure, with lid ground on, pipette and tripod (W. D., Figs. 58 and 59 [53 and 54]j, without measuring glass 0. 3. 0 * :. 1 .7:.o. Disc with hole and glass lid, for showing the divisibility of fuchsia (\V. I)., Fig. 56 [51]) 0. 2. 0 51.751. Double Bulb on stand, Figure, for explaining the expansion of gases by means of red nitrogen peroxide gas (W. D., Fig. 60 [55]), with 2 taps and 1 glass stopper 0. 10. 0 51.752. — idem, without stand 0. 7. 0 « Can be used with the projection apparatus. Cl. . 447, 41*, :K»O. No. 51 767. General Mechanics. 251 51 760. 1 : 6. 51 761. 1 : 6. 51766. 1:10. General Mechanics. (Motion and Forces.) 51.760. Inertia Top, Figure (W. D., Figs. 61 and 62 [56 and 57]), of brass with wood stand for releasing The top runs for 1/2 — 3/4 hour in a space filled with air and for 2 hours in vacuo. The steel bearing in which the top turns must be oiled. 51.761. Carriage with movable rollers (Schultze's), Figure, for demonstrating inertia (Inertia Apparatus) (Fr. phys. Techn. I, 1, Fig. 3170 [I, Fig. 452]), with rail track . 51.762. Mass Apparatus, for explaining the principles of the conservation of the centre of gravity and of live force A large iron block is fixed to a small carriage, a reciprocal motion being imparted to the block by a flywheel and crank. The carriage is also set in motion, the latter travelling on a rail track in a direction opposite to the direction of motion of the mass. 51.763. Apparatus for showing the Resistance of a body in repose to the reception of motion (M. P., I, Fig. 227 [220]), consisting of a lead ball 1 kg weight, with two hooks joined to hemp threads 51.764. Device for proving that an appreciable time is necessary for the change in the condition of motion of a body, Figure on p. 252, as suggested by Weinhold (W. D., Fig. 63 [58]) 51.765. Device for showing the Inertia of a body in repose, Figure . A card is projected away from under a ball by means of a spring, the ball remaining in position. 51,766 Inertia Pendulum (Maxwell's), Figure (Ztschr. f. d. phys. u. chem. U., 18, 1905, P- 148) If the wheel on the suspending threads is rolled in an upward direction and then released, it swings for some time in an up and down direction. 51,767. Spiral Spring, width 10 cm, for demonstrating the force-action of a weight (M. T., p. 31) £ s. d. 2. 15. 0 1. 16. 0 6. 10. 0 0. 5. 0 0. 12. 0 0. 16. 0 0. 18. 0 0. 3. 0 Cl. 450, 452, 451, 55BK. 252 General Mechanics. No. M 708 — 51 768. 1:15. 51769. 1:13. 51771. 1:8. 51 764. 1 : 9. 51.768. Dynamic Balance, Figure, with graduated rail track, adjustable holding pegs £ and two carriages connected by spiral springs (M. P. I, Fig. 80) 5. 0. 0 51.769. Work Rail (Maey's), Figure, with 2 weights (Ztschr. f. d. phys. u. chem. U., 15, 1902, p. 268; Kleiber, Lehrb. d. Phys., 3rd Edition, 1901, Fig. 38), for determining the energy of motion -• 10. 0 One of the weights is twice as heavy as the other. If the lighter weight is allowed to fall from double the height that the heavier falls, the slab (pan of a spring balance) on which the weights fall are depressed to an equal extent. During its downward motion the plate describes a mark in front which remains at the lowest position. 51.770. Pistol for determinations of mass (Grimsehl's), Figure 51,841, p. 263, with shots and weigh pan, graduated (Ztschr. f. d. phys. u. chem. U., 16, 1903, p. 136) . . . .M.771. Double Gun (Grimsehl's), Figure, for kinetic determinations of mass and for ascertaining the relations between force, mass and motion, with 10 shots and 1 cleaner (Ztschr. f. d. phys. u. chem. U., 16, 1903, p. 138) 51,772. Dynmeter (F. C. G. Miiller's), see Magnetism Section, No. 60,133. Dynamometer (Fischinger's), Figure (Fr. phys. Techn. I, 2, Fig. 3292 — 3295 [I, Fig. 457 to 460]). This is a Rotary Steelyard Dynamometer, being arranged between the driving machine or shafting and the work machine by a belt drive, so that readings can be taken by a jockey weight after deducting for the tensile force of the belt. 1. 2. 0 List No. ForCapa- Size cities to | HP For r. p. m. to Tensile Force of Belt kg Belt Speed m. per Second Belt 1 Diam. mm 'alloy Width iiiiu Belt Thickness mm \Vciirht of Dynamo. **• meter ab. kn * 51,773 51,774 51,775 0 8 1 30 2 <>0 1600 960 720 30 100 200 20 24 24 240 480 640 56 110 230 3 4,5 6 - 28 33. 0.0 200 54. 0.0 400 82.10.0 s. d. .~>l,77ii. Band Brake (Braner'g), for efficiency measurements, with automatic arrangement for reducing the tension on the band brake when the friction is over great (Fr. phys. Techn. I, 2, Fig. 3289), Figure .' . 9. 0. 0 Cl. 4092. ,V.i.i 5593, Work, Mechanical Effect. FaU Apparatus. 253 51 781. 1 : 15. 51782. 1:15. 51.777. 2 Fall Cords (Babinet's) (Bohn, Physikal. Apparate aus d. Schaeffer-Museum, Nr. 25, p. 19; Kleiber, Lehrb. f. Gymnas., 3rd Edition, Fig. 373) Of the two cords one is loaded at a distance of 0, 0.5, 2, 4.5 and 8 m from the end with a wood ball. The cord is suspended in a stepped chamber and allowed to fall. The balls reach the floor simultaneously. The reverse experiment is carried out with the second cord weighted at the same intervals. 51.778. Fall Pipes (Newton's), see section dealing with Air Pumps and Accessories. 51.779. Rail Apparatus (Hofler's), see No. 51,807, p. 258 51.780. Fall Apparatus (Barrel's) for determining the time of fall of a sphere by allowing a large number of balls to fall immediately after each other (Aldous, Elementary Course of Physics, London, 1900, p. 46, Fig. 22) *. A ball falling freely actuates the electric releasing device of the next ball at the moment it en- counters the end of its path of fall, so that a fresh ball commences to fall as soon as the previous one has traversed the path of fall. The number of balls are calculated which fall from a certain height in a given time, this number being divided into the time: the experiment is then repeated at different heights of fall. 51.781. Atwood's Fall Machine, Figure, as suggested by Weinhold (W. D., Fig. 64 [59]), with polished scale board, on firm iron stand with levelling screws, device for releasing the fall weights, catch for the excess weights, and receiving platform: with two fall weights composed of 3 single weights of 70, 98 and 98 grammes; with cord pulley of 50 g moment of inertia; with 4 weights, 3 excess and 3 friction weights. In addition to per- mitting of the carrying out the demonstration of the laws of fall proper, the machine can be used for all experiments on Force, Mass and Acceleration suggested by Wein- hold 51.782. - - i d e in, with seconds pendulum on the stand, in Cardan's suspension and with audible seconds beat, Figure The pendulum is also suitable for explaining the pendulum laws; this remark also applies to the succeeding items. £ s. d. 0.10.0 11. 0.0 4. 0.0 3. 0. 0 4. 10. 0 •CI. 455, 462S, 456. 254 General Mechanics. No. 51 783 — 51 783. 1 : 15. 51789. 1:16. 51790. 1:15. 51.783. Atwood's Fall Machine, Figure, constructed in the original Atwood form, without pendulum, with polished wood stand; scale divided in 5 cm; total height of machine: 2m 51.784. --idem, with a seconds pendulum fitted to the stand, in Cardan's suspension and with audible seconds beat r> 1.785. - - idem, seconds pendulum with dial and projecting pointer, audible beat . . . 51,786. -- idem, with friction rollers, without pendulum r>l ,787. - - idem, with friction rollers and seconds pendulum (with audible beat), in Cardan's suspension (Gan.-Man. Figs. 38 — 45; Gan.-Eein. Fig. 61) 51.788. Electromagnetic Release for the Falling Weights, Figure, suitable for all preceding machines, very practical When this electromagnetic release is fitted the hand release given with the fall machines can be dispensed with. The price of the electromagnetic release is reduced in this case by 8 s. to 16 s. 51.789. Large Atwood Fall Machine, Figure, with polished wood base on massive iron stand fitted with levelling screws, rule of maple wood divided every 5 cm. Total height of machine: 2 in. With friction rollers, seconds pendulum with audible beat, dial and projecting pointer; also with electromagnetic release, with key and 3 flexible leads; : £ s. d. 4.10.0 6. 5.0 9.10.0 10.10.0 12. 5.0 1. 4.0 Cl. 57(i:>, 4:.s. r.llul. No. 517112. Fall Machines and Fall Apparatus. 255 51 791 and 51 728. 1 : 15. 51 792. 1 : 12. cord roller of aluminium 100 g in weight, 2 dropping weights of 70 g, to which two weights each of 98 g can be screwed, 4 weights and 3 excess weights The machine is constructed with the very greatest care, and in addition to permitting of the de- monstration of the laws of fall proper allows of all the experiments suggested by Weinhold on force, mass and acceleration (W. D., pp. 74 and 75 [68 and 69]), without the use of friction weights. 51.790. Fall Machine mounted in glazed Cupboard, Figure, travelling on rubber rollers, otherwise as No. 51,789. Own new type This arrangement does away with the troublesome necessity of placing the machine in the museum cupboard; the machine is always ready for use and easily accessible when the cupboard is opened. 51.791. Atwood's Fall Machine, Figure, with levelling screws, on iron wall bracket. The fall posts are easily detachable. Without table, metronome or cell The roller, 100 g in weight, is of aluminium, is most accurately balanced, and runs on friction rollers. The following belong to the apparatus: the two dropping weights of 70 g on to which two 98 g weights can be screwed; also 4 weights and 3 over weights, and electric release. The latter can be operated by means of an electric metronome (see No. 51,726) or a Morse key. 51.792. Fall Apparatus and Seconds Pendulum, with simultaneous electric release (as sug- gested by Edelmann), Figure (Physikal. Ztschr., 1903, p. 413) The falling ball and the body of the pendulum are held fast by an electric magnet, being released simultaneously when the circuit is opened. The ball falls exactly on the pendulum body. £ s. d: 16.10.0 22.10.0 12. 0.0 2.15.0 Cl. 457, 459, 5383. 256 General Mechanics. NIL :.l 7:1:1 51793. 1:13. 51 794. 1 : 7. 51796. 1:18. 51.793. Fall Apparatus (Kottenbach's), Figure (Ztschr. f. d. phys. u. chem. U., 18. £ s fl- 1905, p. 79) 5.10.0 The time of vibration of a slowly vibrating plate spring serves as a measure for the time of fall of an iron ball. In its passage through the position of rest the spring itself releases the ball by means of the electromagnetic release, and at certain heights of fall the ball encounters the spring again in passing through the state of rest, this being annunciated by an electric or mechanical signal. When ordering kindly state whether Electric or Mechanical Signalling is desired. 51.794. Fall Apparatus for Free Fall (Edelmann's), for use with the v. Beetz Tuning Fork Chronograph, Figure, without Tuning Fork Chronograph (No. 51,730) 6. 5.0 At the commencement and end of fall a freely falling ball opens two currents divided by an ; induction apparatus. The induction sparks determine the time-measuring tuning fork curves. Height of fall of ball adjustable from 1 — 60 cm. 51,705. Tuning Fork Chronograph (v. Beetz's), see Fig. 51,730 7.10.0 51.796. Fall Machine (Morin's), Figure, perfectly constructed, for indicating the para- ixila of fall, for ascertaining the acceleration and testing the law of velocities (Chwolson, Lehrb. I, Fig. 211; Fr. phys. Techn. I, 2, Fig. 2234; Gan.-Man. Fig. 33) 18. 0.0 51.797. Fall Machine (F. C. G. Miiller's) (M. T., Fig. 36), with electromagnetic-ally driven tuning fork, for recording the vibration curve on a blackened glass disc. The tuning fork can also be used by itself 4. 0. 0 :> 1,79*. Fall Machine for Free Fall (Pesograph, Lapsometer), Figure (M. P. I, Fig. 83 [81]; Friek phys. Tc-chn. I, 2, Fig. 3456 [I, Fig. 500]) 13. 0. 0 An oscillating pen records the vibration curve on a falling plate covered with paper. cl. Fall Machines. Inclined Planes. 257 51802. 1:21. 51803. I :30. 51 798. 1 : 8. 51804. 1:17. 51.799. Acceleration Apparatus (Bendtorff's), combined with an Atwood Fall Machine (School Science and Mathematics, Vol. VIII, No. 3, March 1908, p. 228) A falling tuning fork (indicating) records its vibrations on a sooted glass plate. The glass plate is capable of lateral motion so that a number of curves can be described on it in succession. The apparatus is supplied with the accessories which are necessary when it is used as a fall machine. 51.800. Tension and Acceleration Meter (Hrabowsky's) (Ztschr. f. d. phys. u. chem. U., 9, 1896, p. 24; Fr. phys. Techn. I, 2, Figs. 3165 and 3166), for graphically demonstrating accelerated motion, for demonstrating the laws of fall, accelerated motion on a horizontal path, equable motion, final velocity, and retarded motion 51.801. Poggendorff's Balance (Fall Machine) for determining the force necessary for accele- rating a body (Fr. phys. Techn. I, 2, Fig. 3275) 51.803. Inclined Plane (W. Konig's), Figure (Ztschr. f. d. phys. u. chem. U., 7, 1893/94, p. 4), with 45 mm diameter lignum vitae ball The inclined plane comprises 4 pieces each 1 m long, which can be inserted one in the other, and 1 piece 0.5 m long. A number of wood blocks, supplied with the apparatus, serve to give the plane different inclinations or to set it up "broken", i. e., with the lower part horizontal. Rotary flags on small stands render the passage of the ball through certain points visible at a distance. 51.804. Quadruple Inclined Plane (Mach's), Figure, for allowing 4 balls to fall simultaneously (Meyer, Naturlehre, Fig. 107, 4th Edn.) Four sliding fillets are supplied with the apparatus so that each ball can be stopped at any desired point. CI. ?.:>7f>. 3299, 462, 4745. £ S. d. 9. 0.0 5.10.0 1.10.0 51,802. Galilei's Inclined Plane for the descent of bodies (as suggested by Bertram), Figure, 1.90 m long (Fr. phys. Techn. I, 2, Fig. 2235, 2236), with variable angle of inclination 1. 8.0 3. 0.0 2.15.0 17 258 General Mechanics. 51 805. 1 : 10. 51 807. 1 : 13. 51,805. Inclined Plane for the descent of bodies (Friedr. C. G. Miiller's), Figure, with track £ B. d. of plate glass, 1 ivory ball and 1 small balance (M. T., Figs. 16 a and 35, and p. 60) 4. o. o 51.807. Rail Apparatus (Inclined Plane), Hoefler's, Figure, for demonstrating the laws of gravitation of the inclined plane; the principle of Inertia, Independence. Reaction,' the Sine Oscillations, etc, (Ztschr. f. d. phys. u. chem. U., 7, 1894, p. 276; Hoefler. Physik, Figs. 1, 6, 36—38 and 52; Fr. phys. Techn. II, 1, Figs. 2194, 3104 a, 3167). with 1 small carriage, 1 spring balance of 20 g mass, 1 long carriage, 1 small table and 1 cord guide with pulley 11. o. o 51.808. Carriage with Spring Dynamometer for above, for measuring the friction (Hoefler- Poske, Fig. 25) . . . 0.15.0 51.809. Apparatus for demonstrating the Fall of a Body through the chord, Figure, with simultaneous mechanical release for the balls 2. 0.0 51.810. -- idem, simple, and without mechanical release (M. P., Fig. 118 [117]) .... 1. 0. o 51.811. Galilean Escapement Pendulum, for showing that the final velocity of a falling body is only dependent on the height through which it falls (W. D., Fig. 72 [65]) (fall on curved path) and for confirming the law of Energy (M. T., Fig. 45), see Fig. 52,123 ... 0. !•!.(> 51.812. Centrifugal Pendulum, for proving the energy of motion (Fr. phys. Techn. I, 2, Fig. 3174) 1. 1 . o 51.813. Apparatus for the Parallelogram of Path and the Composition of Impact Forces, Figure, with 2 hammers and 1 glass ball (W. D., Fig. 65 [60]); M. P. I, Fig. 98; Fr. phys. Techn. H, 1, Fig. 3305) . (1.15.0 51.814. Apparatus for showing the resultant of 2 Directions, F i g u r e, with 2 spring pistols which can lie shot off separately or together. The board is covered with green cloth. being surrounded by a tall beading; with ivory ball 3. 0. 0 51.815. Slab for the Parallelogram of Motions and the projectile path (Penseler's). F i g u r e 1. lo.o A piece of chalk, carried along in a perpendicular rail, and to which a regular upward motion is given or a downward motion influenced by the acceleration of descent, is simultaneously given a lateral nuili in by hand, the resultant appearing as a chalk line. 1 1 ,8 1 ii. Grimsehl's Apparatus for the Composition of uniform and non-uniform Motions (Xtschr. f. d. phys. u. chem. r., 17, 1904, p. 257) 1.15.O Graduated glass slabs can be slid along a board which is placed in a sloping position. If a j;l;i" slab and recording pencil are moved along a definite length in one direction and the' pencil is thru moved along a divided edge of the glass slab in another direction, the point determined by the parallel.. of forecs is reached. Cl. M-' I. 5081. Inclined Planes for the Descent of Bodies. Composition of Forces and Movements. 259 51815. 1:18. 51 817. 1 : 7. 51 821. 1 : 10. 51.817. Apparatus for demonstrating the Composition of two Rotations (Biernacki's), Figure [£ s. d. (Ztschr. f. d. "phys. u. chem. IT., 19, 1906, p. 80), large pattern, suitable for explaining ! Fresnel's explanation of the rotation of the polarisation-plane of light 5. 0.0 51.818. — idem, but smaller 3.10.0 • 1,819. Kinegraph (Engelmeyer's), for recording compound motions, their components and resultants (Ztschr. f. d. phys. u. chem. U., 9, 1896, p. 134; Fr. phys. Techn. I, 2, Fig. 3176) 3. 0.0 51.820. Hartl's Apparatus for recording the Parallelograms of Motion (Ztschr. f. d. phys. u. chem. U., 17, 1904, p. 226; Fr. phys. Techn. I, 2, Fig. 3177) 1. 5.0 51.821. Apparatus for explaining Compound Motions, Figure (Fr. phys. Techn. I, 2, Fig. 2210), with movable stand, so that the diagonals may be set at various lengths, and with graduated arc 2. 5.0 The wing mechanism of theatre stages can be explained with this apparatus. Cl. 3T84, 497, 467. 528Z, 4128, 4S4. 1 7 260 General Mechanics. No, 51 822 B. 1:6. 51 822 A. 1:6. 3; f- 51 824 b. 1:4. 51 824 c. 1:4. 51823. 1:10. 51.822. Circular Motion Diagraph (Salcher's), Figs. A and B (Ztschr. f. d. phys. u. chem. U., £ 17, p. 72), for the composition of two uniform circular motions 10. o. <> Fig. B shows some of the curves resulting from the use of the apparatus. 51.823. Apparatus for demonstrating the Projection Theory (Cosine Theory) of Mechanics (Grimsehl's), Figure (Ztschr. f. d. phys. u. chem. U., 17, 1904, p. 262; Hofler-Poske, Oberstufe, Fig. 21) 51.824. Apparatus for the Parallelogram of Forces and the Pendulum Laws (Weinhold's) (\\ '. D., Figs. 69 A, B, C and 93 [62 A, B, C and 86]) Single prices: 51,8-24 a. Oak Stand (W. D., Fig. 69 B [62 B]), with hooks for pendulums i 0. 12. 0 2. 0. 0 2. 5. 0 .. 2 Rollers on cramps (W. D., Fig. 69 A [62 A]), Figure 51,8-24 c. 13 Double-hook Weights (W. D., Fig. 69 C [62 C]), each 50 g in weight, with 2 cords, ea -h with 1 T-hook and 1 double hook, Figure .-.l.s-24 ,1 3 Brass Balls and 1 Wood Ball on double cords (W. D., Fig. 93 [86]), for explaining the laws of the pendulum ........................................ 0. 3. 0 .M.s-2.".. Parallelograms for above, of pasteboard, graduated (W. 1)., p. 83 [75]) ......... l'."'l> 0. 0. 7 51,82»». Aluminium Ring and 3 Silk Threads with hooks for Varignon's experiment on the parallelogram of forees (M. T., Figs. 9—12) .................. 0. 1. 0 T. Wood Rod, Figure, for the parallelogram of forees (M. T., Fig. 11; Ztschr. f. d. 0. 15. 0 0.1, V II phys. u. ehem. U., 15, 1902, p. 9) 0. 0. in I'l. 4?:.. 17«. 477. I7H, Mil. No. T.1832. Parallelogram of Forces. 261 51 831. 1 : 5. 51 832 A. 1:10. 51.828. 1 Set Hooked Weights, Figure (as suggested by Friedr. C. G. Miiller) (M. T., p. 30), £ »• d. 6 of 10 g each, 6 of 20 g, 4 of 100 g, 2 of 200 g and 2 of 500 g 1. 8.0 51.829. Parallelogram of Forces Apparatus (Frick's) (Fr. phys. Techn. 1, 2, Fig. 2152 [I, Fig. 107]), without weights 1.12.0 (For weights, see 51,824 c.) 51.830. - - idem (Bertram's), Figure, entirely of metal (Fr. phys. Techn. I, 2, Fig. 2154 [I, Fig. 114]), without weights | 2. 0.0 51.831. -- idem, constructed entirely of metal, in the form shown in Fig. 51,831 . . . 2.15.0 If suitable weights be suspended from the ends of the cords of the apparatus, the parallelogram assumes such form that its sides and diagonals are proportional to the suspended weights. 51.832. Parallelogram of Forces Apparatus (S'Gravesande's), Fig. A, with a number of metal bars of various lengths, for obtaining parallelograms of different sizes, with 18 weights, Fig. B, suitable for the apparatus, in one wood block (Fr. phys. Techn. I, 2, Fig. 2150) 4.16.0 Cl. 4518. 6023, 497:.. ITU. is::. 262 General Mechanics. 51 834. 1:12. 51833. 1:16. . 51 832 a. 1:11. 51835. 1:12. 51,832 a. Force Table (Millikan's), with 3 spring balances, Figure . . 51.833. Model (No. 1) for combining forces in space, as suggested by Prof. E. Meyer, Figure (Z. d. V. d. I., 53, 1909, pp. 1301 and seq., No. 1, and text-sheet 13, Figs. 1—3) . 51.834. Model (No. 21) for the equalisation of rotating Masses, Figure (Prof. B. Meyer's) (Z. d. V. d. I., 53, 1909, pp. 1301 et seq., No. 21, and text-sheet 16, Figs. 56 and 57), for demonstrating the equalisation of locomotive driving axles and the discovery of errors in steam turbines and turbo-generators . ' 51.835. Cannon (Grimsehl's), Figure, for demonstrating the action of a couple on a freely movable body (Xtschr. f. d. phys. u. chem. U., 17, 1904, pp. L'l et seq.), with plate glass base, clot hoovered; 2 cannons, 2 shots, stand, steel balls, etc The action of the couple of forces is demonstrated by the recoil which the centre of gravity of the system of masses undergoes when the double cannon is fired off, the ma.->< •- being formed by the ciinnon, a board and a counterpoise. This board rests on steel balls and can be moved in any dire/lion horizontally. Instead of using the double cannon, the single cannon No. 51,837 can be set up on the board for tlie experiment with single forces. 51.836. Couple of Forces Water Wheel (Grimsehl's) (Ztschr. f. d. phys. u. eheia. U., 17, 1904, p. 322), for demonstrating the independence of the action of one or more couples on their position relative to the n\is ut' rotation of the body, and for comparing the action of various large couples 51.837. Reaction Cannon ((IriiuseliFs), for demonstrating the action of individual forces on a movable body (Xlsclir. f. d. phys. u. chem. U., 17, J'.KH. p. 3137); to be used in con- junction with the accessories to No. 51,835 £ s. d. 2. <».<) 8. 0.0 10. 0.0 5.10.0 3. 0.0 51,83*. Projectile Apparatus (Lowy's) (\V. I)., Fig. 66 [61]), Figure The apparatus is employed for proving that a body thrown in a horizontal line is sinniltai n< with the fall of one falling freely. 0. 5.0 0.17.0 cl. a, ma. No. 5184:1. Composition of Forces. Projectile Apparatus. 263 51 838. 1 : 10. •a 51 839. 1 : 5. 51 843. 1 : 14. 51,839. Projectile Apparatus (Haiti's), with spring, for fixing to the wall, Figure (Ztschr. f. d. phys. u. chem. U., 2, 1888/89, p. 81) 5I.S40. Fall Pistol (Projectile Pistol), Hartl's, Figure, for holding in the hand (Ztschr. f. d. phys. u. chem. U., 7, 1893/94, p. 246; Fr. phys. Techn. I, 2, Figs. 3173 and 3180; M. T., p. 63) . . . 51.841. Pistol, Target and Stand, with Rubber Ball, as suggested by Grimsehl, Figure, for studying the trajectory (Ztschr. f. d. phys. u. chem. U., 17, 1904, p. 265) As to the employment of the pistol for determinations of mass, see No. 51,770, p. 252. 51.842. Apparatus (Hagenbach's), Figure, for explaining the influence of the angle of elevation on the horizontal range (W. D., p. 80 [72]) The curves of the projected body are demonstrated by pendulums rorn^ponding to the lengths 1. 4, 9, 16, etc., these pendulums being fixed to a rod at equal distances apart. The rod can be rotated in a vertical plane and forms a variable angle with the divided horizontal bar, the angle being read off on a graduated arc. .">M43. - idem, with diagrams ready drawn for angles of elevation of 0°, 15°, 30°, 45°, 60° and 75°, Figure... The diagrams can, contrary to the illustration, be rolled together, so that the apparatus can easily be moved about, occupying but little space when folded up. £ s. d. 0.18.0 0. 6.0 2. 5. u 1.10. o 3. 0.0 Cl. W, 4TL', 47:t. 264 General Mechanics. ,,. :,iH44 — 51847. 1 : 18. 51 848. 1:10. 51,844. Water Jet Projectile Apparatus, combined with Hagenbach's Projectile Parabola, as suggested by Weinhold (W. D., Fig. 68), Figure 5I.X45. Water Jet Projectile Apparatus (Friedr. C. G. Miillor's) (M. T., Fig. 37) *:,l.si(i. Lantern Slide of the Trajectory of a Krupp 24-cm Gun (M. T., Fig. 33) •~> I. si 7. Apparatus for showing the Projection Parabola (Ducrue's), Figure (Fr. phys. Techn. I, 2, Fig. 3185; Bohn, Physikal. App. No. 28, p. 25) The missle, a chalk ball, rolls out of ;m adjustable bent tube, or is cast out of a straight tube by means of a spring, leaving the parabola traversed on a dead-black board. 5l.si8. Projectile Diagraph (.Salchcr's), Figure (Ztsohr. f. d. phys. u. diem. U., 17, l"oi. page 60) The essential part of the apparatus is formed of a universal parallelograph consisting of 4 bars of equal length and 4 of half this length, linked together. No matter how the .-tainl i- extended, the 4 external points 1, 2, 3 and 4 always define a parallelogram. a s. -.'>hl 51851dl. 1 : 6. 51 851 d 2. 1 : 6. 51 851 f. 1 : 10. 51 851 g. 1:4. 51 853. 1 = 12. 51851m. 1:6. (d) Tackle with aluminium pulleys, with steel axis, in brass frame: 1) 2 Pulley Blocks, each with 3 pulleys, arranged one behind the other, Figure (M. T., p. 33) O.ll'. (i 2) 2 Pulley Blocks, each with 3 pulleys, arranged alongside each other, Figure 0. 15.0 (e) Power Tackle, 4 aluminium pulleys 0. It. 0 (f ) Differential Tackle, Figure, 50 kg carrying capacity, with cast-iron pulley and chain, self-locking 0. 18. 0 (g) Arbor Wheel, Figure, with 3 discs mounted on one axis, the diameters of the discs being as 1 : 2 : 3, of aluminium, with steel axis, in iron clamp: 1) 90 mm diameter ^ 0. 9.0 2) 120 mm diameter 0.10.0 (h) 2 Brass Pulleys on iron cramps, with conical pivots, for the parallelogram of forces, Fig. 51,851, p. 265 (W. D., Fig. 69 A [62 A]), each 7 s. 6 d 0.15.0 (i) 3 Brass Pendulums and 1 Wood Pendulum, on double threads; ratio of lengths 1:4:9 0. (k) Pendulum of variable length, round steel rod with suspension and adjustable brass ball 0. 4. 0 (1) Set of Weights, comprising 20 weights of 50 g each, provided with hooks on both sides, mounted in wood block, 10 of the weights being nickellcd and 10 black varnished, Figure 0.10.0 (m) Hook with cramp, Figure, for suspending heavy objects, electromagnets and the like 0. 3. 0 51.853. Stand with Apparatus for demonstrating the Laws of Meelumics, Figure ... 2. (>. o 1 Stain! i wood), polished, with hooks; 1 Lever with steel axis in metal l»>w. with steel pins passing through at equal intervals apart; also 1 loose and 1 fixed pulley in metal bow; 1 Arbor Wheel with :i sheaves of ratio 1 : '2 : 3; 2 Balance Pans; 1 Pendulum of variable length (brass ball on double thread); G Weights of each 50 g with hooks <>n both sides. 51.854. Universal Apparatus for demonstrating the Laws of Mechanics (as suggested by Friedr. C. (1. Miillei). Figure (Xtsehr. f. d. phys. u. chem. U., 14, 1901, p. 71; M. T., Fig. 33) 6. 0.0 i •iiiiiprisini:: I Stand: I Suspension Device: I Ring made of 1 nun thick brass wire, .'ill cm dia- meter; -2 Similar Rings, 2f> cm diameter; 1 Square and 1 Equilateral Triangle, made of the same sort, For Haiti Indicating Balances with Accessories for experiments »i in Static* and Mechanics, see Xos. 51 597-51 601, p. 240. Ifl7, 488, 4M, 490, BWS, 4018. No. 51862. Universal Apparatus. Inclined Planes. 267 51 856. 1 : 12. 51 859. 1 : 5. 51 860. 1 : 8. 51 862. 1 : 8. of wire, both having 40 cm length of side; 1 Circular Disc of 30 cm diameter, of sheet aluminium; 1 Equilateral Triangular Disc of 30 cm side and 1 Rectangular Disc 10x30 cm; 1 Driving Weight of 10 g, 1 of 5 g, 2 of 2 g, 2 of 1 g; 12 Paper Weights; 1 spare tip, spare thread. The following can be demonstrated with the apparatus: 1) the Fundamental Principles of Me- chanics; 2) the Laws of uniformly accelerated and retarded Motion; 3) Moments of Inertia; 4) the Laws of periodic Oscillations. 51,850. Cycloidal Double Railway (Thierfelder's), Figure, for demonstrating the swinging motion of the Cycloidal Pendulum, of the Parallelogram of Directions and the Impact Action, with 3 steel balls, 2 electromagnets, cell, switch on terminal board and connect- ing leads (Ztschr. f. d. phys. u. chem. U., 21, 1908, p. 244) The railway consists of two hinged parts which can be set up at any angle relative to each other. The electromagnets can be moved along the cycloidal track, being actuated simultaneously by a switch. 51.857. Demonstration Apparatus for the Statics and Dynamics of Rigid Bodies (Topler's) (Ztschr. f. d. phys. u. chem. U., 1, 1887/88, p. 137; Fr. phys. Techn. I, 2, Figs. 3278 to 3281) For proving the hypothesis of the plane polygon of forces, of equilibrium and of the centre of parallel forces, of the equilibrium of couples of force and any forces on the flat or in space, of the prin- ciple of virtual velocities, of the equilibrium of forces on a body rotating on a fixed axis or movable in a fixed direction; of the centre of momentum of motion, of progressive motion, of the action of the couple on the freely moving body, and of uniformly accelerated and oscillating Rotary Motion. 51.858. Accessories for explaining the Centre of Gravity (Eugen Meyer's) (Ztschr. d. V. d. I., Vol. 53, 1909, p. 1301, Xo. 14, and text-sheet 16, Fig. 44) 51.859. Apparatus for proving the Law of the Inclined Plane (Prick's) (Fr. phys. Techn. I, 2, Fig. 2206 [Fig. 121]), Figure The two rollers are in equilibrio, since their weights are as the lengths of the inclined planes pertaining thereto. 51.860. Inclined Plane, simple, with metal roller, balance pan, graduated arc and height rule, Figure 51.861. - - idem, with iron feet, as Fig. 51,863 51.862. Inclined Plane, Figure, of wood, with metal feet, 250 g roller, with 1 tared balance pan and 6 hooked weights each of 50 g (Fr. phys. Techn. I, 2, Fig. 2202) This apparatus has a plain, 2-colour centimetre graduation. s. d. 4.10.0 17.10.0 3.15.0 0.12.0 1.16.0 2. 0.0 2. 5.0 Cl. . 493, 4'.ll. 268 Mechanics of Solids (Statics and Dynamics). 51 869. 1:10. 51 876 A. 1:10. 51 876 B. 1:10. 51.863. Inclined Plane (Weinhold's) (W. D., Fig. 71 [64]), with polished oak stand, carriage £ and loading pan weighing together 500 g, with 2 tared balance pans of each 50 g . 3. 0. o This inclined plane must only be used in conjunction with frame Xo. 51,851 a and pulleys No. 51,851 b. 51.864. - - idem, simpler wood pattern 2.14/0 51.865. Inclined Plane, as No. 51,863, but with a pulley on the upper end. Constructed in this manner the apparatus can be used independently 3. 6. 0 51.866. — idem, simpler wood pattern 3. 0.0 51.867. Plate Glass Slab, Sliding Body and light Balance Pan, for experiments on sliding friction (W. D., p. 137 [116]) 0. 8.0 Tne dull polished glass plate is laid upon the inclined plane so as to afford a uniform bearing surface for the sliding body. The sliding body is of hard wood, and drawing paper is gummed on 3 different sized surfaces, two other surfaces being provided with small hooks. :. l.s«8. Inclined Plane (Bertram's), Figure, entirely of iron (M. P. I, Fig. 267, 268 |2ti-l. 265]; Fr. phys. Techn. I, 2, Figs. 2203 and 2204 [I, Figs. 122 and 123]) 4. 0.0 The bow carrying the guide pulley for the cord can be adjusted so that the force can I"1 applied both parallel to and horizontal with the inclined plane ."> 1.869. -- idem, with graduated arc, Figure I. lu.o 51,870. Inclined Plane (Friedr. ('. O. Midler's), Figure, of wood, with graduated arc. precision roller, small carriage (M. T., p. 36 and Fig. 16) and the following auxiliaries Attachment witli inclined plane, for proving the action of the components of force in propellers, windmills, sailing vessels (M. T.. Fig. 17); Sail Attachment i M . T., p. 37)j Wood Wedge iM. T.. p. 38): Cl. 111'., inn. :.:.L' No. .M SSL'. Inclined Planes. Equal-arm Levers. 269 51 877. 1 : 10. 51 881. 1:10. Couple of Forces Attachment (M. T., Fig. 22); Wood Blocks of 100 g for sliding friction; 1 each respec- £ s. d. tively Slate, Sheet Metal and Plate Glass Slabs; 2 Sets of Wheels (M. T., Fig. 55); 1 Wood Roller (M. T., p. 94). 51.876. Apparatus (Grimsehl's), Figs. A and B, for demonstrating the tensive and com- pressive strain in a solid, and for deriving the momentum theorem (Ztschr. f. d. phys. u. chem. U., 16, 1903, p. 260) 51.877. Apparatus for showing the Invariability of the static momentum on shifting the origin of force in the direction of force, Figure (W. D., Figs. 73 A, B, C [66, A, B, C]) 51.878. Equal-arm Lever, of aluminium, with steel axis and steel pins passing through, lac- quered in two colours, on stand, Figure.. 51.879. Equal-arm Lever, of metal, on iron stand, heavy type, Figure (W. D., Fig. 74 [67]). Without weights For weights, see No. 51, 824 c, p. 260, or No. 51,904, p. 273. 51.880. 2 Metal Levers on metal stands, Figure, with 10 weights, specially suitable for explaining the cooperation of parallel forces and for upwardly directed forces, and for determining the bearing pressure Only one lever is shown in the illustration. 51.881. Metal Lever, in frame, with pulley, Figure, also for forces directed upwards, with weights (Fr. phys. Techn., 7"1 Edn., I, 2, Fig. 2095) 3. 0. 0 51.882. - - idem, without weights 2. 5. 0 For weights, see No. 51, 824 c, p. 260. 2. 5.0 0.18.0 0.10.0 0.12.0 3. 0.0 Cl. 5703, 499, 503, 4S8, 500, 501 270 Mechanics of Solids (Statics and Dynamics;. Nil. .''1 51 883. 1 : 12. 51 886. 1 : 51 884. 1 : 10. 51 888. 1:12. 51 889. 1 : 4. 3. 51.883. Lever Apparatus, for demonstrating the cooperation of parallel forces, Figure, with 12 weights in wood block (Fr. phys. Techn. I, 2, Fig. 2101) 51.884. Lever Stand, Figure, for forces directed upwards and downwards; stand with lever, 3 arms and 3 pulleys, on box, with drawer For weights, see Xo. 51, 824 c, p. 260, or No. 51,904. 51,886. Apparatus fdr explaining the Different Levers and the Balance (Flick's), Figure (Fr. phys. Teclm. I, 2, Fig. 2096 [I, Fig. 91]), of metal (without weights) j 2. i. (l. 5.0 2.15.0 .") I ,X87. - - i d e in, of wood 51.888. Angle Lever, Figure (W. D., Fig. 76 [69]), of metal, stand with levelling screws. I 'rice, excluding weights 51.889. Lever Apparatus (Bertram's), Figure, for explaining the balance beam, entirely of metal 51,891. Apparatus for the Theory of the Moments of Torsion and the Conditions of Equilibrium, a> Miggested by Haiti, Figure (Ztschr. f. d. phys. u. cheni. I"., 14, 1901, p. 321) I Wood Fnmie. I Stand with Circular Discs, 1 Cardboard !>isc with polyjron of forces on both sides. 1 I, ever. 1 Arbor Wheel. 2 C. I. Supports. 4 Hooked Weights each with 4 5o c; and 1 25 g weight for itddincr. -2 Hooked Weijrlit^ of i'u j;; 3 Pulleys on cramps; 1 Equilihrisin;; Weight with hook: Tnreads with eqnilibrised hook-. :>1.S92. Arbor Wheel (Kriedr. C. (J. M tiller's) (M. T., p. 42), the two wheels arc mounted on one shaft with a space between 51,893. Precision Pulleys (Friedr. C. G. Muller's), Figure (M. T., Fig. 8). Price per two 1. 5.0 I. (i 1. 8.0 1.16.0 7.10.0 0.12.0 1.10.0 CI. ."''C. ."''"''. no Lever Apparatus, Arbor Wheel, Tackle, Pulleys. 271 51891. 1 : 14. 51 894. 1 : 12. 51895. 1:11. 51896. 1:11. 1.894. Tackle Frame, of iron, Figure, strongly constructed, with outfit 1 Frame; 1 set Tackle, consisting of 2 blocks each with 3 pulleys in series; 1 set Tackle of two blocks of each 3 pulleys placed in parallel; 1 set Differential Tackle, of metal; 6 loose Pulleys for forming the power tackle and other combinations of pulleys. 1.895. Power Tackle with 4 iron pulleys, Figure, massively constructed 1,896. Tackle with 2 iron blocks, each with 3 pulleys in parallel, Figure, massively con- structed 1.898. Differential Tackle, massively constructed, lifting power 100 kg, also adapted as a model for instruction in mechanics, cf. Fig. 51,851 f 1.899. 6 Loose Pulleys, of iron, for setting up the power tackle and other combinations of pulleys. Each 4 s. 0 d. . £ s. d. 4. 0.0 0.18.0 0.18.0 2. 0.0 1. 4.0 See also Pulleys, Tackle, etc. on pp. 265 and 266, and Screw Tackle No. 50,116, p. 21. in. :i:io2. 4r,44. Ml. MX. 50il. 272 Mechanics oJ Solids (Statics and Dynamics). No. ftl 51900. 1 : 10. 51 901. 1 : 7. 51 905 1 : 4. 51 902. 1 : 10. 51,900. Wedge Apparatus (Frick's), Figure (Fr. phys. Techn. I, 2, Fig. 2216 [I, Fig. 127]), £ with 3 different wedges and 1 balance pan 1. 4.0 51,901. - - idem, of brass and iron, Figure, with wedge-guide (Fr. phys. Techn., p. 721) :> 1.902. --idem (Hartl'.s), Figure, for demonstrating the pressure exerted by both sides of the wedge on the resistance-surfaces, with arrangement for equalising the iron weight of the wedge and for showing the influence of sliding friction (Ztschr. f. d. phys. u. c.hein. U., 5, 1892, p. 282, Fig. 1). Price, without weights There are given in: 3 equal-limb wedges of ratio 3 : 10, 4 : 10 and 5 : 10 of l>;i>'k in side, and one unequilateral. red angular wedge with ratio of sides 3:4: ~>. Cl. 510, 5096, •807, 3. 0.0 4. 0.0 No. 51911. Wedge, Screw, Equilibrium. 273 51 909 A. 1:5. 51 906. 1 : 6. 51 910. 1:10. 51 911. 1 : 9. 51.904. 26 Double-hook Weights for Hartl's Wedge Apparatus Those weights can also be used for the experiments on levers, for the parallelogram of forces, etc. 51.905. Wood Cylinder, with paper surface, Figure, for showing the formation of the screw line (Fr. phys. Techn. I, 2, Fig. 2013) 51.906. Screw Apparatus (Frick's) for demonstrating the action of the screw, Figure (Fr. phys. Techn. I, 2, Figs. 2219, 2220 [I, Fig. 130]), without weights 51.907. -- idem, on stand, cf. Fig. 51,908, with loading weights and with one screw . 51.908. -- idem, with 2 screws of different pitch, Figure £ s. d. 1. 6.0 0. 3.0 2. 0.0 2. 0.0 2.10.0 51.909. Screw Apparatus (Hartl's), Figs. A and B, for the formation of the helical line and the mode of action of the screw (Ztschr. f. d. phys. u. chem. U., 15, 1902, p. 318) j 2.15.0 The cylinders forming the female thread are fixed to a base comprised of wood fillets, it being possible to unwind the base. 51.910. Screw Apparatus (Grimsehl's), Figure, for explaining the action of physical forces on the modus operandi of the screw (Ztschr. f. d. phys. u. chem. U., 17, 1904, p. 132) ; 3. 5.0 51.911. Equilibrium Apparatus, for explaining stable, unstable and indifferent equilibrium »(Fr. phys. Techn. I, 2, Fig. 2108) 0.12.0 By placing the spheres upwards or downwards stable or unstable equilibrium can be produced. Models of Screws: see Section 'Models of Machines and Machine Elements". Cl. 3303, S304, 3f,05, 3306, 5529, 589. ] 8 274 Mechanics of Solids (Statics and Dynamics). No. 51 912. 1 : 9. 51 913. 1 : 9. 51 914. 1 : 7. 51 919. 1 : 6. 51 921. 1 : 4. 51 922. 1 : 5. 51.912. Apparatus (Frick's) for Stable Equilibrium (Fr. phys. Techn. I, 2, Fig. 2107 [I, Fig. 96]), i £ * . o 51.920. Rolling Cylinder (Fr. phys. Techn. I, 2, Fig. 2116) 0. 7. 0 51.921. -- idem (Friedr. C. G. Miiller's), Figure, with lead pencil for recording the cycloidal path of the centre of gravity (M. T., Fig. 28) 0. 3.0 51.922. Leaning Tower, of two parts, with plummet (M. P. I, Fig. 187 [185]), Figure 0. 9. o The tower remains standing as long as the centre of gravity is situated ]>ri •]>< •ndirularly over the base. 51.924. 2 Triangles on 1 Stand, Figure, for explaining the position of the centre of gravity 0. s. o 51.925. Equilibrium Figures, of .sheet metal: triangle, rectangle, trapeze, segment, semi-circle, ellipse, ring, with stand 0.1 l.o 51.926. Equilibrium Figures, of brass, F i g u r e, with centre of gravity constructed on them: circle, triangle, square, trapezoid and pentagon, with cap for setting on :i stand fitted with a point (Fr. phys. Techn. I, 2, Fig. 2105), with stand 0. lli.d 51.927. 3 Centre Of Gravity Figures, of sheet /inc, with holes on the edges, for suspending, and .! Centre of Gravity Figures, of wire (M. T., p. 44) . . . 0. (l.o 51.928. Stability Apparatus (VVcinhold's) (W. D., Fig. 77 [70]), Figure 1. 10.0 ( 1 .!(), .VII. .-,112. Centre of Gravity, Equilibrium, Arbor Wheel, Balance Beam. 275 51 932. 1:10. 51 935. 1 : 8. 51,929. Board with 3 Prismatic Blocks of various heights for stability experiments (Kleiber, Lehrb. d. Phys., Fig. 37) 51,930. Stability Parallelepiped (Lichtenecker's), Figure, consisting of a prism with variable angle of inclination, with centre of gravity plummet 51.931. Stability Prism (Friedr. C. G. Miiller's), with adjustable centre of gravity (M. T., Fig. 29) 51.932. Lever Stand (Friedr. C. G. Miiller's), with auxiliaries for explaining the rod-shaped lever, the disc-shaped lever, the centre of gravity of the lever balance and the pointer balance (M. T., Figs. 20, 21, 23, 27, 30) 1 Stand with 2 rod -shape levers, 1 disc lever, 1 balance beam with pointer, scale, 2 balance pans and 2 rider weights. Hooked Weights: see No. 51,828. 51.933. Arbor Wheel (Friedr. C. G. Miiller's), suitable for previous lever stand (M. T., p. 42) 51.934. Model of a Balance Beam (Weinhold's) (W. D., Figs. 78—81 [71—74]), with iron pillar, beam of ebony, 2 double hooks of 1 and 5 grams and a small rider. £ s. d. 0. 9.0 0.18.0 1. 4.0 3.10.0 0. 3.0 1. 4.0 1.10.0 5 1 ,935. --idem, Figure, with pointer and scale (W. u. E. phys. Prakt., Fig. 27) . For Finished Balances ready for Demonstration Purposes (also suitable for demonstrating the olfl .^^ balance beam), Hydrostatic, Chemico-technical Balances, Sets of Weights, etc., see pp. 231— 244. 4991,595! 18* 276 Mechanics of Solids (Statics and Dynamics). No. :>1 1136 — 51939. 1:8. 51941. 1:9. 51.936. Model of a Roberval Weigh-bridge, Figure ................. 1. 51.937. Model of a Roman Balance, Figure, beam of wood with steel axis, clip and jockey weight of metal, with weigh pan ........................ 0. 51.938. Roman Balance, Figure, for carrying 25 kg, with 2 hooks, entirely (•(instructed of iron, with steel knife edges, calibrated and suitable for practical use ...... 0. 51.939. Model of a Platform Weighing Machine, Figure (Trapeze balance after Quintenz) 1. 51.940. -- idem, different form, Figure .................... . 1. 51.941. - - i (1 c m, entirely of metal, with balance pans on the rods for explaining the dif- ferent lever conditions, Figure ........................ ; 2. •r.l,!t42. Centrifugal Railway, with wood ball, Figure (Fr. phys. Techn. I, 2, Fig. 3188) 0. r>!,!»13. Centrifugal Railway, with small loading carriage. Figure ........... l. Cl. 5523, SS.M!. .MK. 600, tn, a. d. 6.4) is. (i 1C. 0 10.0 10. o ll.o Ki.o No. 51917. Balance Beam. Centrifugal Force. 277 51942. 1:13. 51943. 1:10. 51944. 1:11. 51 946. 1 : 12. 51 945. 1:10. 51.944. Apparatus (Schleiermacher's), Figure, for showing that the centrifugal force is inversely proportional to the square of the speed (M. P., 9th Edn., I, Fig. 135; Fr. phys. Techn. I, 2, Fig. 3267 (I, 446]) 51.945. Centrifugal Force Apparatus (Bruno's), Figure, for introduction to the relations between Force, Mass and Acceleration (Vierteljahresberichte des Wiener Vereins zur Forderung des physikal. u. chem. Unterrichts, X, 4 (1905); Ztschr. f. d. phys. u. chem. U. 19, 1906, p. 299) ........ An accurately measuring apparatus for determining the centrifugal force. 51.946. Regulator Model (as suggested by Prof. Eugen Meyer), Figure, for proving the surface law, specially suitable for demonstrating the increase of angular velocity with decreasing moment of inertia (Z. d. V. d. I., 1909, p. 1301 et seq., No. 15, Fig. 45 on text-sheet 16) 51.947. Centrifugal Apparatus for 2 samples (M. T., p. 72), with glasses and screw clamps Cl. 5735, 3316, 642, 5554, 5050. £ s. d. 2.15.0 21. 0.0 '«>. 0.0 1. 2.0 278 Whirling Tables and Accessory Apparatus. No. Slew 51 949 A. 1:9. 51 952. 1 : 8. 51 949 B, 52043. 1:6. 51 948. 1 : 5. 51 959. 1 : 8. 51,948. Central Force Electromagnet and Iron Ball, the latter arranged for suspension, £ B. d. Figure (M. P. I, Fig. 125) 1. 15. o If the pendulum is moved from the position of rest and then simply released, it swings to and fro in a straight line; if it is submitted to a slight lateral motion, it describes an ellipse, the most distant focus of which lies over the point of the magnet. If the lateral motion is stronger, circular motion results, and if still greater, elliptic motion again takes place, and the tip of the magnet lies below the nearest focus. Whirling Tables and Accessory Apparatus. The machines have a massive iron frame, and they can be used both horizontally and verti- cally; in the latter case they are screwed on to the table. The rotating parts are most carefully (•(instructed; the axis being most accurately machined and ground in so as to run quite true. Bach of the pieces of auxiliary apparatus made by us fits every machine which we construct. If we arc required to fit apparatus to whirling tables constructed by other makers, it is desired that the axis may be sent us, if the apparatus have only to be fitted to the axis. The frame is bored through laterally from the axis, this boring being provided with a thread for taking various devices on either side. There are supplied with the machines a disc with pin for inserting in the axis of the whirling table and with nut for fixing siren-discs, colour-discs, a stroboscopic cylinder, or the like to the lower end of the axis; also a hook at the lower end of the axis for suspending pendulums, etc. Special attention may be directed to the larger Machines Nos. fd.it.V.i et se<|., which can be screwed horizontally to the table and thus admit of being employed in many different wa\ s. In order to show the many-sided uses of the whirling tables, the following apparatus, taken from all branches of physics, can be used with the tables, and we would remark specially that they mostly replace isolated apparatus, and are therefore much cheaper than the latter. ri. 5681. Whirling Tables. To pages 278 and 279. 62 ' Notice. NEW! Whirling Table NEW! with Electric Motor Drive and Double Wheel Gearing. A. For Direct Current. In the construction of this new pattern Whirling Table care has been taken that the revolutions of the machine can be altered within the widest limits without the power applied to the axis dimi- nishing appreciably. In the case of hand-driven Whirling Tables the speed and power can be chosen ;it will. If, however, the whirling table is driven by an electric motor, it generally runs at too great a speed for most experiments. If the speed of the motor is decreased by inserting a resistance, the power applied to the axis is correspondingly reduced, and, in addition, the speed is influenced in various manners by friction. A satisfactory mode of driving is therefore unobtainable in this manner. These conditions are considerably ameliorated by our fitting the machine with a simple intermediate gearing which considerably decreases the speed of the motor. The machine, however, was only rendered perfect by fitting it with a double gearing. There are thus two driving pulleys running at different speeds at our disposal. The speed of the two pulleys is as 1 : 4. The gearing of the motor axis on the first driving pulley is 3 : 10. The speed of the motor can be further regulated within wide limits by a controlling resis- tance. By selecting this arrangement it is possible to vary the speed of the whirling table between 30 — 1100 r. p. m. From numerous exhaustive experiments we have found that these limits suffice for all experiments. The wheels are constructed partly of "Vulcan- fibre" with a view to reducing noise to a minimum. 8951 A. 1:9. 8951 B. 1:6. The whirling table has a massive iron frame and can be used both vertically and horizon- tally. Fig. 8951 A shews the whirling table arranged vertically, ready for use and for taking a colour disc, siren discs, or the like; while Fig. 8951 B shews the machine placed horizontally. The rotating parts are constructed in the best possible manner; the axis is very carefully machined and ground in so as to run true. The arrangement of the axis and the fixing of the auxiliary apparatus are the same as before. Auxiliary apparatus already available fit this machine without any alteration. The frame is bored out laterally to the axis, and is tapped for taking different devices on either one side or the other. A disc with pins for inserting in the axis of the machine, and with nut for fixing siren discs, colour discs, a stroboscopic drum, or the like, also a hook fitted to the lower end of the axis, for suspending pendulums, etc., are given in with each whirling table. The Electric Motor is fixed to the frame of the whirling table by means of a slider. The slider can be moved by a screw, thus allowing the driving cord to be tightened or loosened. The regu- lating resistance, a switch and a plug box are firmly fixed on the frame. This arrangement com- bined everything necessary for working and the machine can be connected at once to the electric supply: it is only necessary to set up the machine where it is desired to use it, connect the current lead fitted to it to the electric supply with the aid of the plug contact, and the Whirling Table is ready for use. No further wire connections require to be made beforehand. The weight of the motor renders the machine so firm that it is only in exceptional cases necessary to screw it down to the lecture table. In order to ensure the machine a firmer position and to prevent scratching the lecture table, it is fitted with rubber feet. M. 62 6. Cl. «207. 6224. To pages 278 and 279. Whirling Tables. The manipulation of the Whirling Table fitted with electric motor has been found to be most advantageous since the experimenter has both his hands free and does not require to remain in t he immediate neighbourhood of the machine in order to explain the phenomena being demonstrated, but can even go to the blackboard. The arrangement of this machine presents the further advantage that the motor can be used. without removing it from the stand, for driving the influence machine or other apparatus, and this at any speeds. Fig. 8051/60435 shews an influence machine being driven. The Whirling Table fitted with motor drive is manufactured in two sizes: Fig. No. S!C>1 shews the smaller pattern, which is sufficient for most experiments. Whirling Tables with D. C. Electric Motor Drive, Figs. 8951 A and B and 8951/60 435; small Pattern, with electric motor, compound wheel gearing, regulating resistance, switch, plug contact and J metres flexible. Qf Hp ^ 1/g ^ 1/g Pressure, Volts 110 110 220 220 List No. 8951 8952 8953 8954 With D. C. Motor With D. C. Motor Price, £ 7.0.0 8.0.0 7.10.0 8.10.0 If the pressure is different from above the prices are varied accordingly. Large Whirling Tables with D. C. Electric Motor Drive, with electric motor, compound wheel gearing, regulating resistance, switch, plug contact and 2 m flexible, for connecting up to Direct Current. Of HP Vl6 V. Vl6 Vg Pressure, Volts 110 110 220 220 List No. 8961 8962 8963 8964 Price, £ 8. 0. 0 9. 0. 0 8. 10. 0 9. 10. 0 The prices are proportionately changed when the pressure varies. B. For Alternating and Three-phase Current. From the point of view of construction the Whirling Tables having Alternating Current Motors do not differ in any way from those for Direct Current. The special nature of the A. ( . motors does not, however, allow quite such a wide degree of variation in speed as the D. C. motor. For this reason and, more especially, because in the case of the A. C. motors, the power decreases with diminution in speed, it is desirable to give the preference to a Whirling Table with D. C. motor in all cases in which Direct Current is available or can be easily provided. 8951/60435. 1:12. 8965. 1 : 8. Fig. 8965 shews a Whirling Table driven by Alternating Current. The speed can be varied from about 80 — 1000 r. p. m. On three-phase networks A. C. motors arc also used, being connected up to one phase only. This is permitted by most electricity works in view of the low efficiency of the motor in question. Whirling Tables with A. C motor drive, Fig. 8965; small Pattern, with electric motor, compound wheel gearing, regulating resistance, switch, plug contact and 2 metres flexible, for connecting up to an A.C. network or to one phase of a three-phase supply. Wit li A. C. Motor, i Of HP Vio Vio Frequency 50 I Pressure, Volts 110 (100 pole alternations List No. 8965 8966 per second) Price, £ 9. 10. 0 10. 0. 0 Large Whirling Tables with A. C. Motor Drive, with electric motor, compound wheel gearing, regulating resistance, switch, plug contact and 2 metres flexible, for connecting up to an A. C. network or to one phase of a three-phase supply. With A. C. Motor Frequency 50 ( 100 pole alternations per second) »Of HP V10 Pressure, Volts 110 I^l No. 8967 Price, 1 10. 10. 0 220 8968 11. 0. 0 C'l. 11229, 11227. No. Centrifugal Force. Whirling Tables. 279 51 960. 51 969, 51 949, 51 975, 52 035. 1 : 7. 51.949. Whirling Table, for hand drive, Figs. A and B, small pattern (W. D., Fig. 75 A; Fr. phys. Techn. I, 2, Fig. 3195) 51.950. --idem, with 3-stage Pulley (M. T., p. 66) . . Whirling Tables, driven by Electric Motor, Figure, small pattern, with plug contact and 2 m flexible. VM With D. C. Motor and Begulator-Starter of HP Pressure List No. Price £ 110 51,951 6. 10. 0 110 51,952 8.0.0 220 51,953 6. 15. 0 Vs With A r TVTntnr VVUI1 A. i,. ITlOlOr, ( Of HP i/.. Vs V,e Freauencv 50- Pr^sure .110 110 220 witE Stfrter' Lpst *°" «#» *£** ^ Price £ 6. 15. 0 8. 5. 0 7. 0. 0 If pressure and current differ from above the prices vary to correspond.1) 220 Volts 51,954 8.5.0 220 Volts 51,958 8. 10. 0 £ s. d. 1.15.0 2. 2.0 51.959. Large Whirling Table, Figure, with massive frame, length: 80 cm, width: 37 cm, with two screw clamps on the frame for firmly clamping the machine in a vertical position. A clamp for clamping the table in a horizontal position is given in . . . j 51.960. - - idem, with wide feet, Figure, for standing upright on the table instead of clamping; can also be used horizontally Large Whirling Table, with Electric Motor Drive, Figure, length: 80 cm, width: 37 cm,! with 2 screw clamps on the frame for firmly clamping in a vertical position; a screw clamp for horizontal clamping is given in. 3.^0.0 3. 5.0 With D. C. Motor, without Tachometer, but with Eegulator Starter With A. C. Motor, Frequency 50—, without Tachometer or Starter of HP Vi- Vs Pressure HO 110 List No. 51,961 51,962 Price £ 7. 15. 0 9.5.0 of HP Vi. Vs Pressure 110 110 List No. 51,965 51,966 Price £ 8.0.0 9. 10. 0 220 51,963 8.0.0 v« 220 51,967 8.5.0 Vs 220 Volts 51,964 9. 10. 0 Vs 220 Volts 51,968 9. 15. 0 If the current and voltage differ from those given the prices undergo a corresponding alteration.1) The illustration no longer shows the actual construction; the transmission of motion from the I horizontal to the vertical axis is effected by a bevel gear system with gearing on the low speed and with a simple cord drive. 51,969. Cord Gear, for rapidly rotating Colour Discs and the like, suitable for whirling tables Xos. 51,949— 51,958 and 51,959—51,968, cf. Fig. 51,969; without colour discs or whirl- ing table 1. 0.0 The illustration shows that the larger cord pulley of Apparatus Xo. 51,975 is used as well. This ( apparatus is not included in the preceding price. ') Existing whirling tables with A. C. motors can be used ou 3-phase networks by using ri. 5207, only two leads. 5064, un. 280 Whirling Tables and Accessory Apparatus. No. :.i HO 51 972. 1 : 8. 51977. 1:10. 51978. 1:7. 51979. 1:10. 51.970. Counting Mechanism, Figure, fitted to the preceding whirling tables; after every £ s. . 3:!I7, 4lis7, i:!2». :>71*. No. 51998. Whirling Tables and Accessory Apparatus. 281 51 993. 1 : 8. 51983. 1:6. 51 987. 1 : 51 996. 1 : 6. 51 997. 1 : 6. 51.980. Whirling Apparatus with 8 Spherical Pendulums, for showing that the centrifugal force £ » <1 increases with speed of rotation, and is higher when the radius of rotation is large than when small, the time of run being the same in both cases 0.10.0 51.981. Pendulum Race (Puchs'), with double-cord pendulums of various lengths, the balls of which are always raised to the same height (Ztschr. f. d. phys. u. chem. U., 16, 1903, p. 343; Fr. phys. Techn. I, 2, Fig. 3222) . 0.10.0 51,98-'. Watt's Pendulum, Figure (W. D., p. 101 [93]) 0.11.0 51.983. Watt's Ball Governor, with a complete throttle flap valve, in section, Figure (M. T., p. 71) 1. 8.0 51.984. Angle Lever Apparatus (Fr. phys. Techn. I, 2, Fig. 3203 [I, Fig. 426]) 0.16.6 51.985. Spring Balance, for showing the strength of centrifugal force, Figure (Fr. phys. Techn. I, 2, Fig. 3200) 0. 15. 0 51.986. - - idem, Hartl's, for measuring the centrifugal force (Ztschr. f. d. phys. u. chem. V., 10, 1897, p. 123; Fr. phys. Techn. I, 2, Fig. 3204) 2.10.0 51.987. Centrifugal Balance, Figure 0.18.0 . 1 ,988. - - idem (Friedr. C. G. Miiller's) (M. T., Fig. 39), with variable centrifugal mass and rule for measuring the radius of swing 1.12.0 51.989. Emery Disc for hardness tests: can also be used for grinding small tools (M. T., p. 51) 0. 6.0 51.990. Flattening Ring, Figure (W. D., p. 102 [93]) 0. 7.0 51.991. Sphere of Glycerine Clay, with suspension (W. D., Fig. 84 [77]; M. T., p. 71) . . 0. 6.0 51.992. Apparatus for showing the oblateness of a sphere of oil and Saturn's ring .... 1. 0. 0 This apparatus is well adapted for showing the flattening of plastic rotating bodies. 51 .993. Glass Vessel for Mercury and Coloured Water, Figure (Fr. phys. Techn., 6lh Edn., I, Fig. 546; M. T., p. 70) 0. 4.0 51.994. Glass Balloon for hanging on the lower end of the axis 0. 4.0 Tiie vessel is filled with water and closed with a sheet of cardboard, the air-pressure preventing its escape. On rotating the balloon the cardboard can be taken away without any of the water escaping. 51.995. Cylindrical Attachment, with rule: can be used as a tachometer (M. T., p. 69) . . - 0. 5. it 51.996. Angle with 2 obliquely placed tubes for mercury and coloured water, Figure (Fr. phys. Techn., 6th Edn., I, Fig. 545; M. T., p. 70) 0. 7. 6 51.997. Siphon, with marking rings, Figure (M. T., Fig. 41) j 0. 9.0 51,99*. Attachment with 3 disconnected tubes (M. T., Fig. 42) 0.12.0 CI. 5731, 5729. .'.325. 65u', 4961, 5728, 57J2. 282 Whirling Tables and Accessory Apparatus. No. ">] 11119 - 51 999. 1 : 7. 52000. 1:10. 52 002. 1 : G. 52 003. 1 : 5. 52 008. 1 : 12. 52 009. 1 : 5. 52 015. 1 : 8. 51,999. Apparatus (Bertram's) for clearing cloudy liquids by rotation, Figure (M. T., p. 72) The 2 glass vessels are placed horizontally during rotation. 52.000. Model of a Draining and Drying Apparatus, on the centrifugal principle, Figure 52.001. -- idem, (Haiti's), with glass protecting cylinder (Ztschr. f. d. phys. u. chem. I".. 10, 1897, p. 125; M. T., p. 72) 52.002. - - idem, consisting of glass globe and wire netting, Figure 52.003. Model of Ventilator, Figure (W. D., Fig. 86 [79]), with vane wheel 52.004. - - idem, better construction, one wall glazed 52.005. Centrifugal Pump and Centrifugal Blower (Hartl's) (Ztschr. f. d. phys. u. chem. U., 10, 1897, p. 125) 52.006. Wind Vane and Wind Wheel (Friedr. C. G. Miiller's), for demonstrating the Propeller Fan; the wind vane is to be placed on the whirling table and sets the ventilator in motion (M. T., p. 38) 52.007. Apparatus for Stable and Unstable Axes (Hartl's), masses adjustable, for varying tin- centre of gravity and moment of mass (Ztschr. f. d. phys. u. chem. U., 10, 1897, p. 122; j Fr. phys. 'Techn. I, 2, Fig. 3224, 3225) 52.008. Apparatus for Free Axes, Figure (W. D., Fig. 87 [80]) 52.009. Bohnenberger's Machine, Figure, improved by Poggendorff, for placing on the whirling table (M. T., p. 72) 52.010. Apparatus (Sire's) for showing, that rotational motions can generate successive motions, consisting of a top suspended as a pendulum: for the whirling table (Fr. phys. Techn. I, 2, Fig. 3252) 52.011. — i d e m, Koppe's (Ztschr. f. d. phys. u. chem. I".. 4, 1890, p. 77; Fr. phys. Techn. I, 2, Fig. 3253) 52.012. Ring with Hook, for suspending from the lower cud of the axis by a cord (\V. !>.. Fi-. 88 [81]; M. T., Fig. 44) 52.013. Rod with Hook, also for suspension . Pendulum with dissymmetrical system of masses (M. T., Fig. -10) £ s. d. 0.10. (I 0. 15. 0 1. 5.0 0.12.0 0.11.0 1. 5.0 •2. 15.0 0. 9.0 2. 0.0 0. 12.0 1. 7.0 1. 10.0 0.18.0 0. 1.9 0. 1.3 0. 4.0 ci. :.;:,(>. :,:isn, :.7i" ;>7'J7. f..12T, 4-.IH.Y Auxiliary Apparatus for Whirling Tables. 283 52021. 1:5. 52025. 1 : 10. 52017. 1:9. 52028. 1:8. 52030. 1:9. 52.015. Apparatus (Eisenlohr's) for showing that the rotation of the plane of oscillation of £ s d Foucault's pendulum is proportional to the sine, of the geographical latitude: for placing on the whirling table (W. D., Fig. 95 [88]) 1. 5.0 52.016. Pendulum Ball, painted half black and half yellow, for proving the conservation of the plane of oscillation, Foucault's experiment (W. D., p. 117 [108]), for hanging on the lower end of the axis of the whirling table 0. 1.6 52.017. Pendulum for Foucault's Experiment, Figure, with stage and suspension clip . 1. 0.0 52.018. 5 Stroboscopic Discs, with black and coloured moving images 0. 6.0 52.019. Stroboscopic Cylinder (Quincke's) with 1 set paper strips, for demonstrating pendulum oscillations, longitudinal and transverse oscillations, vibrations of ether particles, the reflection of cord undulations, vibrations of strings and air strata in pipes, the vibrations of liquid particles and of successive transverse waves 0. 14. 0 52.020. Strips alone 0. 6.0 52.021. Siren-Disc, of metal, with 4 rows of holes, giving the major chord when blown, F i g u r e, without' whirling table 0. 5. 0 52.022. - - idem, w'th 8 rows of holes, giving the major or minor common chord, or, if specially desired, the chromatic scale , 0. 7. 0 52.023. - - idem, with 4 rows of holes pierced obliquely 0. 9. 0 52.024. Wave Siren-Disc (Konig's), in disc form • . . . 0.15.0 A wave line, formed by the algebraic addition of 4 sine curves, receives a current of air from a slotted aperture, the air being made to vibrate as if 4 tones were sounded simultaneously. The human ear then separates this compound form of vibration into its constituents in such manner that prima, third, fifth and octave are separately heard. 51', 025. Wave Siren-Disc (Konig's), large pattern, of brass, Figure, in various tone ranges Each 3. 6.0 52.026. Siren-Disc (Oppelt's) 0.16.0 52.027. Siren-Disc (Appunn's) 3. 6.0 For complete data regarding siren-discs, see Acoustics Section. 52.028. Savart's Toothed Wheels, 4 wheels mounted on one axis, giving a chord. Wheels of zinc, Figure 0. 9. 0 52.029. - - idem, with brass wheels 0.12.0 52.030. Apparatus for proving Doppler's principle, Figure, as suggested by van Gulik • (Ztschr. f. d. phys. u. chem. U., 14, p. 288), without whirling table 0.13.0 C'l. 1051 1, 659, 5390, 5724, 4963. 284 Whirling Tables and Accessory Apparatus. No. :,i' 52 031. 1 : 7. B 52 038. 1 : 6. 52 040. 1 : 6. i o 52 041 A. 1:6. 52 045. 1 : 7. 52046. 1:10. 52.031. Rotating Mirror Box, 120 mm side of cube, for analysing acoustic flame images, see Figure, without gas-flame manometer 52.032. Rotating Mirror (Reichert's), with only one obliquely placed mirror (M.P.I, Fig. 648 [675]) •V_',033. Gas Flame Manometer with rotating Burner, with rubber hose and sound glass, can be used for flame images without mirror (cf. W. D., Fig. 243 [229]), for the whirling table 52.034. 1 Set Colour Discs, 7 different single-colour discs and 1 with the 7 spectrum tints The single-colour discs are cut out radially as suggested by Maxwell, so as to mix the coloured lights. 52.035. Colour Disc with the 7 spectrum colours, painted as clearly as possible on a metal disc, giving white when rotated, size 120 mm, see F i g. 51,969 .">:.'. 036. — i d e m, size 250 mm 52.037. Disc Apparatus for alternating mixed colours, for the whirling table The colours of a sector disc can be exposed to any proportion by circular sections cut out of a pasteboard disc, and be mixed by rotating. 52.038. Coloured Convex Surface (or Cylinder) (Kolbe's), Figure, serving as complement to the colour discs (Ztschr. f. d. phys. u. clieni. I"., 8, 1894/95, p. 243). without wood cone (see No. 52,040) " Each 52.039. 14 Colour Cylinders (Kolbe's), all different, without wood cone (see No. 52,040). . :•:.'. u Hi. Wood Cone with pins, Figure, fitting the whirling table 1. I. i 1 r.r.sr, c.iii, fiiw. fir,:i, 664, 5723, :>3!i.V No. 52051. Auxiliary Apparatus for Whirling Tables. 285 52 047. l : 0. 52 050. 1 : 5. 52 049. 1 : 8. 52,041. Screen of Bristol Board, graduated, Fig. A, and with 2 sliders, F i g. B, on adjust- able stand 2,042. - - idem, without stand 52.043. Oscillating Prism, Fig. 51,949 B, p. 278, for mixing the spectrum tints (M. P., 8th Edn., 11,1, Fig. 137), the prism being 60x30 mm. Price, without whirling table 2,044. --idem, 70 x35 mm 52,045. Glass Globe with a solution of Glycerine and Soap (as suggested by Eisenlohr), Figure (Fr. phys. Techn., 6th Edn., II, p. 788), for demonstrating Newton's rings of thin liquid films The glass glote should be slightly warmed before the experiment is made until large soap films form when it is shaken. One of these films is introduced into the upper half of the glass vessel so that it is vertical to the axis; if now the globe is carefully rotated by means of the whirling table the film referred to shows the colour rings in a very beautiful manner. 512.046. Phosphoroscope (Becquerel's), Figure (M. P., 9th Edn., 11,1, Fig. 257), with stand and universal clamp for firmly fixing the various bodies 5L'.i»47. Polarisation Apparatus, Figure, for demonstrating the properties of polarised light, for the whirling table (M. P., II, 1, Fig. 671 [634]) 512.048. Apparatus for boiling by friction water, alcohol or ether (W. D., Fig. 417 [393]) . 512.049. - - idem, wnth arrangement for igniting the vapour of the alcohol, Figure . 512.050. Apparatus (Puluj's) for determining the mechanical equivalent of heat, Figure, with a thermometer divided in 1/10° and a screw clamp with pulley, for setting on the whirling table (W. D., Figs. 418—421 [394—397]) The inner cone is completely insulated by ivory rings. The apparatus is constructed in a thorough manner, and the experiment can be made with great accuracy. £ s. d. 0. 9.6 0. 4.6 1. 5.0 1.10.0 0. 7.0 2,051. - - idem, with Whirling Table 2. 0.0 1.10.0 0. 5.0 0. 6.0 5. 5.0 7. 0.0 Cl. 5321, 667, 668. 286 Whirling Tables and Accessory Apparatus. 1 52 052 A — 52054. 1:8. 52 052 B, 52055. 1 : 10. • 52,052. Apparatus (Puluj's), exactly as No. 52,050, with Whirling Table Xo. 51,959, driven by electric motor, F i g s. A and B, with 110 volt D. C. Motor and starter for n-.iriilatin.ir the speed, without wood stand, balance pan, spring balance or screw clamp .... Prices quoted on application for different voltages and types of current. :>!.', or>3. Wood Stand with iron tripod, see F i g. 52,052 A : . . . . 52.054. Spring Balance for 0 — 250 grams, see Fig. 52,052 A 52.055. Balance Pan, 50-g weight, see F i g. 52,052 B. For frame, sec No. :.l ,851 a, and pulley with screw clamp, see No. 51,851 h 52.056. Apparatus (Rosenberg's), Figure, for explaining the theory of cyclones, anti- cyclones, monsoons and anti-monsoons (Ztschr. f. d. phys. u. chein. I"., 12, 1899, pp. 335 to 338), without whirling table Complete description and directions for use on application. £ s. d. 13. 0.0 n. <;.<> 0. 4.0 (I. L'.li 1. 1(1.0 Cl. :»l'<7, 3683. No. 52 ,20«0. Auxiliary Apparatus for Whirling Tables. 287 .. J 52056,51949. 1:9. 52057, 51949. 1 : 10. 52058. 1 : 10. 52 059. 1 : 9. 52 060. 1 : 5. 52,057. Rotating Device for large Geissler Tubes of 30 — 50 cm long, Figure, with well insulated lead, for induction coils giving a spark of 40 — 100 mm 52.058. Disc (Poggendorff's), illuminated by Geissler tube, Figure, for proving that the light emitted by Geissler tubes is only apparently continuous (M. P., 9th • Edn., Ill, Fig. 763), with one Geissler tube 0.15.0 52.059. Apparatus for Arago's Magnetism of rotation, Figure (W. D., Fig. 560 [533]) . 1. 4.0 An adjustable glass slab with magnetic needle is arranged over a large rotating copper disc1. On rotating the disc the needle is deflected in the direction of rotation, being itself finally set in rotation. 52.060. Rotating Magnet, with rotary copper disc above it, Figure (Fr. phys. Techn. II, 1, Fig. 1086) 1. 0.0 Cl. 669. 670, 5721, ' 5719, 674. £ s. d. 1.18.0 288 Whirling Tables and Accessory Apparatus. No. T.2061 — 52 06ir 1 : 7. 52 062. 1 : 8. 52 065. 1 : 7. 52 064. 1 : 7. 52 086 A. 1:8. 52 066 B. 1:8. 52 067. 1 : 7. Apparatus for generating Focault Currents in a copper disc rotating between the poles of an electromagnet, Figure When the circuit of an elestro-magnet is closed, a large amount of power is necessary to rotate the disc very rapidly. r»2,<)«2. Apparatus for Unipolar Induction, Fessel and Pliicker's, Figure, with 2 rotating bar magnets (M. P., <)lh Edn., Ill, Fig. 584) ................... 52,063. Apparatus for Earth Induction, with rotary wire spiral and commutator, for taking off direct current (Fr. phys. Techn. II, 1, Fig. 1118) ............... .~i2,<)64. - - idem, with commutator and slip rings, Figure, for taking off direct and alternating current ............................... :>L'.()<;r>. Pacinotti's Ring, as suggested by Biihlmnnn, Figure, with conductor springs (Fr. pliys. Tedm. II, 1, Fig. 1138), without horse-shoe magnet and vertical galvanometer When the ring is rotated ;md a magnet held above, a galvanometer joined up with tlic conductor springs gives a considerable deflection. .">-', odd. Apparatus for explaining the Magneto - electric and Dynamo - electric Principle, Figs. A and B .............................. The apparatus consists of: (a) 1 Pacinotti ring ...................... (b) 1 Magnet ... ...................... (<•) I Klectni-magiift ......... • ............ , 0. (d) 1 Brush Conductor ..................... I 0. 1. . o 15. 0 II. i;73. M22. 676, 675, 677. B7«, tn. Auxiliary Apparatus for Whirling Table, Moment of Inertia. 289 R'Scmf -J ( '• ?i)G«w.«Og. I* --2dm.— «i Gew.735g. 2'icni. 52 069. 1 : 5. 52 070 A. 1:17. * 32cm. - — * (|Antriebgew.50g. 52 070 B. 1 : 12. 52071. 1:15. 52.067. Model of Pacinotti-Gramme Machine, Figure, as suggested by Pfaundler (M. P., 9th Edn., Ill, Fig. 659 and 660), for the whirling table, with device for rendering visible the lines of force; this apparatus can be recommended for explaining the dynamo. Price, without whirling table The following pertain to the apparatus: an iron armature with winding, an iron armature, un- wound, a wood armature with winding, and a frame with paper stretched across for demonstrating the lines of force. 52.068. Model of a Short-circuited Armature in the Magnetic Field, Figure, Friedr. C. G. Miiller's (M. T., Fig. 222), for setting on the whirling table, with a squirrel-cage rotor which can be used either with or without an iron core 52.069. Rotating Thermocouple, Figure, cylindrical form, of iron and German silver, with contact spring sliding along the cylinder When the apparatus is rotated the cylinder becomes heated by the friction of the spring, thus producing a current which flows from the iron to the German silver according to the position of the spring. 52.070. Apparatus for determining the Moment of Inertia, Hartl's, Figs. A and B (Ztschr. f. d. phys. u. chem. U., 6, 1892, p. 74, and 5, 1891, p. 76) The test pieces (rings, discs, bars, rectangular plate) the moment of inertia of which it is desired to determine can be fixed to a spoke-cross. The release is electro-magnetic. Given in with the apparatus are 6 test pieces, 2 falling weights, 1 Morse key and leads. 52.071. Moment of Inertia Apparatus (Kurz'), Figure (M. P. I, Figs. 291, 292 [280, 281]), with cords, 2 loading weights each of J/2 kg and 2 kg, and an excess weight of 50 g; apparatus 2 m high For Apparatus for demonstrating the laws of continuity and of inertia, see also p. 251. £ s. d. 6.10.0 2.10.0 0.15.0 9. 0.0 3. 10. Cl. 4684, 680. 602, 603, 3896. 19 290 Mechanics of Solids (Statics and Dynamics). No. 52U7:; — 52 075 A. 1:10. 52 073. 1 : 5. 52 076. 1 : 13. 52 075 B. 1 : 30. 52.072. Pendulum for Moment of Inertia (Weinhold's) (W. D., p. 112 [104]), iron rod with £ * <'• axis in the centre, with 2 bobs each 0.981 kg and 3 bobs each 0.245 kg in weight, with iron stand and Cardan suspension 2. M.o 52.073. Apparatus for determining the Moment of Inertia by means of torsional oscillations, Figure (W. u. E. phys. Prakt., Fig. 66), for mirror-reading 2. o. u The duration of oscillation of the system is observed by means of a telescope \vith cross wires. first with these bodies, and then without them. This apparatus is employed in conjunction with a massive frame,, e. £., N'o. .">:_'. 195. 52.074. Moment of Inertia Apparatus (Grimsehl's) (Verh. d. Physikal. Gesellsch. VI, Nos. 15—19; Ztschr. f. d. phys. u. ehem. U., 18, 1905, p. 35) 4. n.o The discs, arranged so as to rotate, only execute translatory motions when the system is in oscillation; if the discs are firmly fixed, the total mass only of the system is taken into consideration in determining the moment of inertia. 52.075. Rotating Disc and Weighted Bar, as suggested by Prof. L. Prandtl, Figs. A and B, for showing the relations between Angular Velocity and Moment of Inertia (Ztschr. d. Vercins dcutscher Ingenieure, 1909, pp. 1301 et sc<|.. No. 16, and Figs. 46 and 47 on text-page 16) 5.1o.o 52.076. Apparatus for the Surface Principle, as suggested b\ I'rol. Hug. Meyer, Figure. for proving that a rotating mass imparts in an opposite din-el ion an angular velocity in a co-axial ly rotary mass, this angular velocity corri->pomliiiir to the ratio of the moment of inertia. With 110 volt D. ('. motor (ZtBChr. d. V. d. I., 53, iw.i. pp. 1303 et wq., Xo. 17. and text-sheet 16, Fig. 48) 8. 0.0 Cl 51*. .Miii'.i. 55511. No. Moment of Inertion, Surface Principle, Counteraction, Tops. 291 52 080. 1 : 3. 52 082. 1 : 6. 52 083. 1 : 3. 52 084. 1 : 8. 52.077. Counteraction Apparatus (Fuchs'), for demonstrating the Surface Principle (Ztschr. £ s. d f. d. phys. u. chem. TL, 15, 1902, p. 218; Fr. phys. Techn. I, 2, Fig. 3277) .... 52.078. Schmidt's Top, Figs. A and B (W. D., Figs. 89 — 92 [82—85]), with stand and suspension 1. 5.0 1. 2.0 52.079. --idem, Figure, in ring, with stand, can also be used suspended from a cord 1. 0. 0 52.080. 3 Tops of different sizes, for placing over each other, Figure (Fr. phys. Techn. I, 2, Fig. 3248 [I, Fig. 438]) 2. 0.0 52.081. - - i d e m, with stand and suspension for 1 top, as No. 52,078, and with pointed attachment and brass rod (Fr. phys. Techn. I, 2, Fig. 3249) 2. 8.0 52.082. Model for explaining the main phenomenon in the Gyroscope, F i g u r o, as suggested by Hammerl (Ztschr. f. d. phys. u. chem. U., 1892, p. 68) 1.10.0 52,083. Schmidt's Top with Hollow Sphere of sheet iron and with stand, Figure (Fr. phys. Techn. I, 2, Fig. 3234 [I, p. 513]) . . . j 1. 4.0 If it is attempted to place the sphere in another plane, with the moving top, by turning the ! hand, a resistance is felt as if the axis of the top were held firmly in its position by unseen forces. 52,084. Gyrostat (Gray's) Figure (Fr; phys. Techn. I, 2, Figs. 3235, 3236) C. 0.0 Cl. 605, 806, 607, 609, 5«32, 6'J8, 498 j. 19* 292 Mechanics of Solids (Statics and Dynamics). No. Bans:,.— 52 086. 1 : 7. 52 089. 1 : 6. 52 088. 1 : 3. 52 092. 1 : 8. 52 093. 1 : 5. 52,085. Curve Top (Koppe's) (Ztschr. f. d. phys. u. chem. U., 4, 1890, p. 80; Fr. phys. Techn. I, 2, Fig. 3244) 52.086. Fessel's Top, Figure, with 1 ring (Fr. phys. Techn. I, 2, Fig. 3239) 52.087. - - idem, with 2 rings I £ s. d. 2.10.0 2. 0.0 2.10.0 52.088. Bohnenberger's Apparatus, with excess weight, for explaining the conservation of the plane of rotation, with stand, Figure (Fr. phys. Techn. I, 2, Fig. 3243; M. P. I, Fig. 319) If the disc is set into rapid rotation, the axis of rotation preserves its position in space, even if the apparatus is moved in any manner by raising and turning the base. If required to act as a Fessel top, the ring must be firmly fixed. 52.089. - - idem, improved by Poggendorff (Eisenlohr, Fig. 78), Figure, with device for driving 52.090. - - i <1 <• in, for the whirling table, see No. 52,009, p. 282 52.091. Top, as suggested by Schliek (Skutsch's model) (Ztschr. d. V. d. I., 52, 1908, p. 464) 52.092. Polytrope (Sire's), Figure, for combining a number of rotations (Fr. phys. Techn. I, 2, Fig. 3254) The apparatus has a spur drive and allows of demonstrating the following: 1) That the axe> of rotation endeavour to take a parallel position. 2) That the rotations always take place in the same direction, thus showing: (a) the determination of meridian, (b) the determination of the iri •ii^ra- phical latitude of any pl.i -e. (c) the invariability of the plane of rotation, (d) the earl h's own rotation, (e) the conical motion of the earth: the nocturnal equation, nutation, (f) parallel progressive motion of the earth's axis in space. 1. 8.0 3. 0.0 i 1. 7.0 Trice on appli- cation. 12. 0.0 Tops, Pendulum. 293 52 094. 1 : 5. 52 095 B. 1:4. 52099. 1:16. 52 098. 1 : 10. 52.093. Polygonal Pendulum (Gruey's), Figure, in cavdanic suspension, with frame (Fr. phys. Techn. I, 2, Fig. 3384) If the top is wound up and the pendulum rotated out of the vertical, the point of the pendulum describes a stellate, spherical polygon; if the top is not rotating, the pendulum swings as an ordinary pendulum. 52.094. Conical Pendulum (Gruey's), Figure, with frame . The suspension of the top, of rubber, is twisted a number of times and the top released in a vertical position without any jar. The pendulum then describes a gradually widening cone, which again becomes narrow until the suspension cord is twisted in a vertical position in the opposite direction and a reverse motion of the pendulum takes place, etc. 52.095. Top Apparatus (Wanka's), Figs. A and B, with stand, for setting up and with special clip device for suspending the top (Ztschr. f. d. phys. u. chem. U., 11, 1898, P- 235) Each top can be fixed in the three main positions perpendicular to each other. 52,096. Alternating Gyroscopic Tree (Gruey's) (Fr. phys. Techn. I, 2, Fig. 3250) 52.097. - - idem, the top being rotated by its own weight instead of by rubber cords . 52.098. Pendulum Stand, Figure, light wood frame, with 3 brass balls and 1 wood ball, on single cords 52,099. --idem, of iron, Figure, with 6 pendulums on double threads, on massive base, with adjustable swivels for the cords Two pendulums with discs hanging in different planes, 2 with bobs, each 900 mm long, and 2 shorter, viz., 400 and 100 mm long respectively. £ s. d. 3.10.0 2.10.0 2.14.0 5. 0.0 5. 0.0 0.15.0 0.18.0 Cl. 33 U, 3945, 4Kf>3, «17, 616. 294 Mechanics of Solids (Statics and Dynamics). X... 5! 52102. 1:12. 52105. 1:12. 52 109. 1 : 14. 52,100. Frame with Pendulums, of. F i g. 51,850, p. 265 (W. D., Fig. 93 [86]), with 3 brass balls and 1 wood ball on double threads 52.101. 4 Pendulums, as No. 52,100, separately, for use with frame No. 51,151 52.102. Pendulum Frame (Friedr. C. G. Miiller's), Figure, with 4 brass balls, 2 of these with 2 hooks and 2 with 1; 1 wood ball with hook; 1 lead ball with hook; 1 bearing for reversing pendulums; 1 knife-edge for disc pendulums, wire figures, etc.; 1 angle piece; 4 spiral springs for demonstrating the spring pendulum; 1 physical and 1 re- versing pendulum; 1 disc pendulum (M. T., Figs. 46 and 51) 52.103. Pendulum for explaining the Laws of the Pendulum, simple type, iron rod, graduated, with adjustable bob and wall arm 5LM04. Maxwell's Pendulum The pendulum consists of a rod 80 cm in length, the upper end of which can turn about an axis. A cord can be wound round this axis and a metal ball suspended from the cord, so that tin- periodicity of both pendulums can be made to coincide. 52.105. Pendulum with directly measurable length, Figure, Grimsehl's (Ztschr. f. d. phys. u. chem. U., 18, 1905, p. 36) The pendulum has two knife-edges, 1m apart; the, pendulum is hung upon the- upper knife - edg<-, tin- hob resting at its centre of gravity on the lower one, thus the pendulum only undergoes a translatory, small circular motion when swung. The moment of insertia of the disc is negligible when the pendulum is swinging. The pendulum accordingly swings like a mathematical pendulum the length of which is equal to the distance between the two knife-edges. 52.106. Compensating Pendulum, on stand, pendulum 0.5 m long: see No. 51.;i . . . 52.107. - - idem, with 9 brass and steel rods, beating l/» seconds: see Fig. 51,695, p. 215 Kindly compare the Pendulum Stands for fitting to the Lecture Tables Nos. 50.097 and 50,098, pp. 18 and 19, Frame No. 51,151, p. 206, and 51.851, p. 265. For Seconds Pendulums, see Section --Measurement of Time", pp. '24.', and -Mil. £ s. d. 0.15.0 0. 3.0 3. 4.0 0. 18. 0 0.12.0 5.10.0 1. 4.0 2. 10. 0 and the I, .Mm',, r.lli No. .',2113 a. Reversing Pendulums. 295 I 52110. 1:15. 52112. 1:13. 52113. 1:16. 52 113 a. 1:18. 52.108. Reversing Pendulum (Weinhold's) (W. D., p. 115 [106]), of wood, with wall bracket 52.109. - - idem, Prick's (Fr. phys. Techn. I, 2, Fig. 3356 [Fig. 476]), Figure, iron rod with 2 knife-edges and graduation, with 2 bobs (lead) and wall arm suspension . . 52.110. - - idem, can also be used for experiments on the moment of inertia, Figure, with 2 bobs each of 1 kg weight, 2 bobs each of 0.25 kg, and a small bob, with stand and Cardan suspension (Fr. phys. Techn. I, 2, Fig. 3354 [I, Fig. 477]) . 52.111. Demonstration Pendulum (reversible), of brass and iron, for showing the laws of motion of the compound pendulum, swing I1/, seconds, with stand 52.112. Reversing Pendulum (Kater's), simple pattern, Figure, with 1 bob and two ad- justing weights, in Cardan suspension, on stand with levelling screws 52.113. Reversing Pendulum (Kater's), Figure, well and substantially constructed: length between knife-edges, exactly 1 m; the weight adjusted by micrometer screw; graduation with vernier, with wall bearing and arresting device. The total length of the pendulum is 1.7 m (Gan.-Man., Fig. 58). In box, without stand 52,113 a. - - i d e m, with stand and box, Figure 12. 0.0 14. 0.0 Cl. 620, 621, 1122, 5281. £ s. d. 0. 9.0 1. 0.0 2. 8.0 6. 5.0 2.15.0 296 Mechanics of Solids (Statics and Dynamics). No. 52114 — 52 116. 1 : 8. 52 117. 1 = 8. 52118. 1:6. 52120. 1:14. 52123. 1:10. 52 124 A. 1:15. 52.114. Sheet Iron Pendulum (W. D., Figs. 94, 73 B and C [Figs. 87, 66 B and C]), for proving, £ that the periods of swing are equal for axes parallel to each other at the same distance apart from the centre of gravity; the pendulum suspended as in Fig. 51,877, p. 269 0. !.">.(> 52.115. -- idem, without suspension, assuming that Apparatus No. 51,877 is available . 0. 8.0 52.116. Pendulum Apparatus (Ilillig's), Figure, for demonstrating the change of velocity of a swinging motion, with stand and adjustable glass plate (Fr. phys. Techn. I, 2, Fig. 3460) 4. (i.o A load pendulum is suspended on a frame in such manner that it swing* accurately in a plane. The pendulum weight has a spring which can swing easily and -write on a blackened glass plate. (In one side of the frame is an arresting device for releasing the pendulum weight, this devid- l>ein<: arranged -ii ihiit the pen is released simultaneously i>y the lock action. An arresting device ia fitted at the otnei side of the frame, for catching the pendulum. The tracing style leaves a waxy line behind it on the glass slali; on the return journey, during which it docs not exert a -u inking motion of itself, it traces an arc. which cuts the sine line. The individual sections on this arc (pendulum line) are the tracks traversed by the pendulum during equal periods and they therefore demonstrate the various pendulum velocities. ci. IIL-:I. ii-M. B2->. :.c,7i'. .V.7I. .'.7WI. Single and Double Pendulums, Vibrations. 297 4:5 5:6 6:7 52 124 B. 52 126. 1 : 12. 52127. 1:13. 52,117. Pendulum Apparatus (Mach's), Figure, with adjustable pendulum plane and graduated arc (M. P. I, Fig. 150 [157]; Fr. phys. Techn. I, 2, Fig, 3343 [I, Fig. 479]) ."•2,118. Cross Pendulum (Oberbeck's), Figure, for demonstrating the laws of the physical pendulum (Ztschr. f. d. phys. u. chem. U., 1, 1887/88, p. 253 ; Fr. phys. Techn. I, 2, Fig. 3355 [I, Fig. 480]) 52.119. - - i d c in, without stand, for use with the Mach pendulum apparatus stand No. 52,117 52.120. Spring Pendulum (Prof. Eug. Meyer's), Figure, for demonstrating the individual periodicity of a system, the periodicity of a periodic force, the forced oscillations, the static deflection, resonance and the critical periodicity of a force (Z. d. V. d. I, 53, 1909, pp. 1301 et seq., No. 18, and text-sheet 16, Fig. 49) 52.121. Model for Ship Oscillations, as suggested by Schlick (Z. d. V. d. I., 53, 1909, p. 1301 et seq., No. 20, and text-sheet 16, Fig. 51) .">-', 12.3. Galilean Escapement Pendulum, Figure: see also No. 51,811, p. 258 52,1.24. Double Pendulum (Airy's), Figs. A and B (Fr. phys. Techn. I, 2, Fig. 3389 [I, Fig. 493]), for demonstrating Lissajous' curves by means of blue sand .">2.125. -- idem, without stand, for drawing the curve by ink (M. T., Fig. 50) . . . . 52.126. Double Pendulum (Oberbeck's), Figure, for demonstrating co-oscillation (Fr. phys. Techn. I, 2, Fig. 3398 [I, Fig. 496]; Ztschr. f. d. phys. u. chem. U., 1,1887/88, p. '254) 52. 127. Double Pendulum (Lorenz'), Figure, for studying combined oscillations on the flat, specially suitable for the oscillations of bells and clappers £ s. d. 1.10.0 1. 4.0 0. 16.0 2. 5.0 Price on appli- cation 0.14.0 1. 0.0 0.12.0 1. 0.0 6. 0.0 Cl. 627, 6iC, Mi:.. 298 Mechanics of Solids (Statics and Dynamics). 52 128. 1 : 5. 52 129. 1 : 4. 52.128. Apparatus for Foucault's Pendulum Experiment, Figure... The 10 cm diameter iron ball, weighing about 4 kg, is suspended from an iron plate by means of a fine steel wire. By unscrewing a milled screw this ball can be removed from the wire. The centre of gravity of the ball is determined in mercury. The sheet metal disc is covered with sand during the experiment. In ordering, please state length of suspension wire desired. 52.129. -- idem (Weinhold's), Figure (W. D., Figs. 96—98 [89—91]) 4. 5.0 The accurately turned, cast iron ball, 10 cm in diameter and weighing 4 kg, is fastened to a steel Cardanic suspension by means of a fine steel wire. This ball swings over a paper-covered metal disc which can be raised by a lever. A brush, filled with coloured glycerine, and inserted in the ball, leaves a coloured line behind only when the plate is raised. £ s. d. 2.10.0 52,130. - - idem, with 20 cm diameter ball, weighing 30 kg, suitable for lofty rooms . * 52,131. Apparatus (Edelmann's) for Foucault's Pendulum Experiment, for objective pro- jection, Figure (Wied. Ann., 45, 1892, p. 187), with device for projecting . . . A magnet is inserted in the pendulum underneath. When the pendulum is swinging the niii.nnei swings over a soft-iron knife-edge fitted on the rotary vertical axis. By magnetic attraction this knife- edge is always brought into the predominating plane of the pendulum. 9.10. (I 52,132. Projection Device, separately 5.10.0 52.133. Contact Device, Figure, for the balls used in the Foucault pendulum experiment, as suggested by Weinhold (W. D., 4th Edn., Fig. 99; Ztschr. f. d. phys. u. chem. U., 17, 1904, p. 198), with stand .......................... 1. Contact is effected by the internal friction of a liquid (coloured water). 52.134. Haiti's Model for explaining Foucault's Gyroscope (Pendulum) Experiment (Fr. pli\>. Techn. I, 2, Fig. 3259) ............................. 52.135. Torsion Pendulum with Accessories, as suggested by Friedr. C. G. Miiller, comprising an iron rod and a circular disc with clamp (M. T., Fig. 52), with lead weights inserted. with 4 suspension wires of 3 different materials 52.136. U-Tube for oscillations of liquids (M. T., Fig. 49) 0. 52.137. Apparatus for demonstrating and explaining the harmonically Oscillating Motion of the projection of a point moved in the circle on a straight line, as suggested 1>,\ \\eiler, Figure (Ztschr. f. d. phys. u. chem. U., 20, 1907, p. 105) L. If the handle on the back of the disc is turned the hurmoiiie motion e;m be followed. 0.0 o.o 0.0 8.0 lli.H Can be used with (lie Projector. For Apparatus for Foucault's Pendulum Experiment, suitable for the Whirling Table, see Nos. 52,015-52,017, p. 283. ;. c No. 52141. Foucault Pendulums, Harmonic Motion, Resonance. 299 52 137. 1 : 6. 52 131. 1 : 3. 52 140. 1 : 10. 52138. 1:14. 52 139. 1 : 6. • .".I1, i:;,s. Apparatus for projecting harmonic vibration (sine vibration), as suggested by Hofler, Figure (Hofler, Physik, Figs. 30 and 243; Hofler-Poske, Figs. 12 and 144) . . . For demonstrating the composition of two sine vibrations, two of the above apparatus and two projectors are necessary. 52.139. Resonance Top (van Schaik's), Figure (Ztschr. f. d. phys. u. chem. U., 7, 1893/94, p. 181). Price, exclusive of vice The top is loaded on one side and produces considerable vibration, according to the free length of the spring, and at high or low speed. 52.140. Resonance Top (Frahm's), Figure (Glaser's Ann., Vol. 59, 1906, pp. 697 et seq.) The rotating disc of the top is loaded on one side, so that the top when held in the hand makes a considerable amount of vibration. A so-called Frahm comb with six spring tongues is fixed to tin- top, these tongues having different numbers of vibrations. With decrease in the number of vibrations one spring after another vibrates. The principle is used in speed measurements on prime movers, and when the tongues are electri- cally excited by means of an A. C. magnet, it can also be applied to frequency measurements. 52.141. --idem, in velvet case For use with the projection apparatus. £ s. d. 2. O.-O 1. 2.0 2. 5.0 2.10.0 Cl. 633, 3751. 3785. 3K-5, 5446, 3947. 300 Mechanics of Solids (Statics and Dynamics). No. :.:M!L' 52 144 A. 1:9. 52 144 B. 1 : 5. 52,142. Resonance Apparatus, as suggested by Prof. Bug. Meyer, for demonstrating torsional vibrations of elastic waves by resonance (Z. d. V. d. I., 53, 1909, p. 1301 et seq., No. 19, and text-sheet 16, Fig. 50) i. S. (1. 6. 15. 0 52,143. Analysing Apparatus for vibrations, as suggested by Grimsehl, for analysing the vibra- tions of tuning forks, strings, etc., and for determining the frequency of sirens, He. by a photographic method (Ztschr. f. d. phys. u. chem. U., 17, 1904, p. 33) 1. 8.0 52,144. Apparatus for Cavendish's Experiment on the Attraction of Mass (Gravitation Balance), as suggested by Boys, F i g s. A and B (Ztschr. f. d. phys. u. chem. U., 14, 1901, p. 381; M. T., p. 86) 15. o.(t Two small silver balls, each 0.75 g in weight, are suspended by means of a very fine quartz fibre from a fine balance beam (torsion balance). The whole is enclosed in a glass case and has a firsi rate arrestment device so that the instrument can be carried about from one place to another without fear of damage. The small balls are influenced by large lead balls each 2800 grams in -weight which can be moved along a frame to the two end positions by cords. In order to make the deflections visible to a large audience, an image of the filament of a glow lamp is produced on a scale fixed to the wall by the aid of a bi-convex lens and a light mirror fixed on tin apparatus. To give an idea of the sensitiveness of I lie apparatus, we might mention that an apparatus installed in our test room gave a preliminary deflection of ' s of the scale distance in one direction when the lead balls were moved from the centre to one of the end positions; alter some movement to and fro of the balls the luminous pointer stopped at about 21 cm to the left or right according to the direction of movement of the balls. The scale distance in this case was only 2.25 m. -- Com- plete directions for use are given with each apparatus. .M-M45. Attraction of Mass Apparatus, Wrinhold's (\V. I)., -l<" Kdn., Fi, !>TTO, 304 Molecular Effects of Solids. No. :,'2 176 — 52176. 1:8. 52 179 A. 1 : 20. 52 179 B. 1 : 20. 52 180. 1 : 13. 52,176. Apparatus for determining elasticity in bending, Figure (W. u. E. phys. Prakt., Fig. 63) The apparatus consists of two wood blocks fixed on boards, those blosks being fitted with clamps for screwing down the wires; the blocks can be weighted by means of weights. In addition the fol- lowing pertain to the apparatus: 1 vertical scale on base, one pointer for sliding along the rod to bo tested; 3 steel rods and 1 copper rod. Weights not included in above price. 52.177. --idem, with small glass scale, graduated in Microscope No. 51,474 The soalc is fixed to the rod instead of the pointer. 52.178. One Set Weights, suitable for No. 52,176 and 52,177 mm, for reading with Reading £ s. (1. 1. IL'.O 2. 0.0 1. 5.0 52.179. Transverse Strength Apparatus, as suggested by Prof. Fug. Meyer. F i g s. A and B, for explaining the calculation of the transverse strength of straight bars, also for ex- plaining the conception of bending moment (Z. d. V. d. I., 53. 1000, p. 1301 el se<|.. No. 3, and text-sheet 13, Figs. 7 and 8) 6.15.0 The wire maintained in tension at one end is loaded at the other end, Pig. A. The end of the bar in tin- clip is then moved up to a nick F, at which the l>;ir run be dismounted: and forces of such direction and magnitude are applied to the loaded portion that the portion of the bar in the original position is again in a state of equilibrium. F i g. B. 52.180. Bent Crankshaft, as suggested by Prof. Kug. Meyer. I-' i g 11 re. a model for demon- strating the bcndini: moment, the turning moment and the thrusts in a crankshaft (Z. d. V. d. I., 53, 1000, pp. 1301 et se«,.. No. }. and text-sheet 13, Figs. 10—12) . . 10. i:>.0 Tile crankshaft can be divided in the centre of the crank pin in order to explain the actions of the individual forces at this section. Registering Apparatus for Sag in Bridge Constructions, etc. quoted for on application. . Wi38, Elasticity of Bending, Bending Strength, Forces on Bearing. 305 52 181. 1 : 14. 52 182 A. 1:10. 52 182 B. 1 : 10. 52183. 1:18. One half of the crank-shaft is taken forward, the other half being again brought to a state of equilibrium in the original position by the introduction of single forces and couples, after removing the bearing, so that all forces present and their action can be plainly demonstrated. 52.181. Bending Model (Prof. Eugen Meyer's), Figure, for demonstrating the deformation of a bar by submitting it to bending: consisting of a bar formed of a number of parts held together by springs which when loaded on one side form the elastic line as a poly- gonal line (Ztschr. d. V. d. I. 53, 1909, pp. 1301 et seq., No. 5, and text-sheet 13, Figs. 13—15) Instead of using the steel springs a brass spring can be used whose coefficient of expansion is greater than that of the steel springs, so as to be able to analyse the conditions in the bending of cast iron bars. Wood bars can be placed on the model which become as tangents on the elastic line or which give the direction of the radius of curvature of the elastic line. 52.182. Crankshaft with moving parts, as suggested by Prof. E. Meyer, Figs. A and B, for explaining the deformation of a crankshaft (Ztschr. d. V. d. I. 53, 1909, pp. 1301 et seq., No. 6, and text-sheet 14, Figs. 16 — 22) The model is provided with joints at the sections" to be considered, so that the deformations caused by all the prevailing forces can be shown separately. 52.183. Apparatus for Determining the Statically Indefinite Forces on a Bearing, on a bar with three bearing surfaces, as suggested by Prof. E. Meyer, Figure (Ztschr. d. V. d. I. 53, 1909, pp. 1301 et seq., No. 7, and text-sheet 14, Figs. 23—25) We will assume that the magnitude of the bearing force in the centre of the bar loaded as in the illustration with P, and P« is to be determined. The centre bearing is taken away and the sag caused in the middle is measured by PI and P2; PI and P2 are then shifted and a force W is applied to the centre which tends to bend the bar in an upward direction just as much as it was bent down- wards by P, and P2. If P,, P, and P3 are applied simultaneously the resultant deflection is obtained from the algebraic sum of both at zero. £ s. d. 6.15.0 5. 5.0 4.10.0 Complete description of Prof. Eugen Meyer's models on application. Cl. 5643, 5641, 5646, 5651. 20 306 Molecular Effects of Solids. X.i. :.L'184 — 52184. 1:10. 52185. 1:10. 52 186 A. 1:12. 52 186 B. 1 :12. 52 187. 1 : 13. 52.184. Model for Demonstrating Mohr's Law on the Elastic Line, as suggested by Prof. £ s 7. and text-sheet 14, Fig. 26) 5.10.0 The bar resting freely on bearings at the points a and b, loaded with the weight P, assumes the same elastic line as the chain carried over the same bearing, since its horizontal tension is equal to the modulus of elasticity, and as the line of load of the chain is equal to the line of the -•- deter-. J mined for the bar. 52.185. Rivetting Model, Prof. Eugen Meyer's, Figure, for explaining the strain on the chord rivets and the shearing stress in compound girders which are submitted to a bending strain (Ztschr. d. V. d. I. 53, 1909, pp. 1301 et seq., No. 9, Figs. 31 and 32, and text-sheet 14, Figs. 28 — 30) 5. 5.0 The rivet submitted to the different stresses can be taken out and it is possible that the shearing or compressive stress present in the cross sections ee, ff, and which the rivet must take up can be ascertained by a lateral movement of the angle iron with the chord piece opposite the web sheet. In like manner the shearing force present in the section gg can be shown by loosening the connection. 52.186. Breaking Model (Bach's), Figs. A and B (Ztschr. d. V. d. I. 53, 1909, pp. 1301 et seq., No. 10, and text-sheet 14, Figs. 33 and 34), for showing that the resistance to breaking strain is inversely proportional to the square of the length of the bar ... 1. 15. 0 On loading the bars, which are gripped vertically, stable equilibrium occurs between the bending moment of the load and the elastic forces, either when the bars are in an extended or a curved posi- tion; — or — when the load is considerable — a condition of equilibrium does not take place and the wood bars are fractured. Test bars are given in with the apparatus, these comprising bars of various material in lengths of 30 and 60 cm. 52.187. Apparatus for Demonstrating Resistance to Breaking Strain of Bars, as suggested by Prof. Michel, Figure 8. 0.0 With this apparatus the resistance to breaking strain of bars of different lengths, varying section, and of different materials can be determined and the bars can be gripped 'either on one side, or both • •nds can be left free and be guided in the original axis or both ends can be gripped and guided in the original axis. 52,187 a. — idem, with automatic supply of the load 1 10. 10. 0 Complete description of Prof. Eugen Meyer's models on application. Cl. 5654, Xo. :a in. Bending, Breaking, Tension. 307 52188. 1:10. 52 189. 1 : 12. 52 190. 1 : 13. 52191. 1:12. 52.188. Model for Explaining Tension, as suggested by Prof. Eugen Meyer, Figure (Ztschr. d. V. d. I., 53, 1909, pp. 1301 et seq., No. 11, Fig. 35, and text-sheet 14, Fig. 35) The rubber plate submitted to the forces PI, P2, P3 and P4 has a cut in the direction a — b and forms a gap.' The division of the forces working on the cut into normal tension and shearing stress is explained. 52.189. Apparatus (PrandtPs), for Demonstrating the Angular Changes at the edges of a body by shearing stresses occurring in pairs (Ztschr. d. V. d. I. 53, 1909, pp. 1301 et seq., No. 12, Figs. 36 and 37, and text-sheet 14, Figs. 38 and 39) The apparatus consists of a system of spiral springs arranged between two glass discs as in the illustration. If these are pulled as shown in the illustration no angular changes result at the corners A, B', C' and D; this case corresponds to ordinary bending. Shearing forces can be applied at the same time; in this case angular changes also take place at the corners, i. e., the right angles are sometimes acute and sometimes obtuse. 52.190. Apparatus for Demonstrating the Deformation of a Parallelepipedic Body on the end surfaces of which normal shearing stresses act simultaneously, as suggested by Prof. Eugen Meyer, Figure (Ztschr. d. V. d. I. 53, 1909, pp. 1301 et seq., No. 13, and text-sheet 13, Fig. 42) A base plate (angle iron W) can be raised and thus intercepts all the weights, and accordingly the elastic slab is unloaded and it assumes its original rectangular shape. 52.191. --idem, Figure, constructed as per Fig.~43 in the publication mentioned . Complete description of Prof. Eugen Meyer's models on application. £ s. d. 1.15.0 Price on appli- cation 10. 0.0 6. 5.0 Cl. 5660, 5661, 5663, 5664. 20* 308 Molecular Effects of Solids. No. 52 192 — 52201. 1:10. 52 195. 1 52,192. Apparatus for Determining Young's Modulus, F i gu r e, with the aid of the catheto- meter (Chwolson-Pflaum, Lehrb. d. Phys., 1904, Vol. 1, p. 700) Rubber, steel and glass are given in as test materials. £ s. d. 9. 0.0 52,193. Apparatus (Spring's), for proving that a peimanent deformation (plasticity) increasing with time takes place when the elastic limit is exceeded, Figure (Fr. phys. Teehn. I. 2, Fig. 2254 [I, Fig. 137]) 17.1(1.0 The apparatus consists of a massive oak frame, an iron T-shaped girder the thicker end of which is curved upwards, and a wrought iron downing-levi r which MTV< s as bearing. The latter is loaded at its free cud with weights, as shown in the Figure, while the point of pressure is as close as possible to the fulcrum. The pressure exerted can be easily calculated from the dimension. The apparatus and a pressure mould, supplied by us, admit of a pressure of 10,000 atmospheres. The necessary weights are included in the priee of the apparatus. 52,194. 2 Bars for Comparing Torsion of Elasticity, as suggested by Friedr. C. G. Miillcr (M. T., p. 50), with clamping device 0. 2. II IIKM. .Mis». 690, 892. No. 52202. Elasticity. 309 T 52 196. 1 : 16. 52199. 1:10. 52 202. 1 : 5. 52.195. Apparatus for Determining Torsional Elasticity, Figure (W. and E. phys. Prakt., Fig. 65) The apparatus is (not as shown in figure) built into a massive frame 1.4 m high and has an adjustable tension clip at the top for the wire to be tested, 3-stage aluminium disc, ribbed and gra- duated, 2 rollers turning about pillars and 1 vertical rule. Six different wires and 1 set of perforated lead weights pcrtair>. to the apparatus. 52.196. Apparatus for Determining Torsional Elasticity, Figure The apparatus is constructed in a similar manner to No. 52,195. Four scales can be fixed to the wires to be tested at equal distances. Weiler uses it (as per Ztschr. f. d. phys. u. chem. U. 11, 1898, p. 282) constructed in this manner as a mechanical model for demonstrating the potential drop in electric conductors. 52.197. Apparatus for Testing the Torsional Strength of Metal Bars, Friedr. C. G. Miiller's (M. T., p. 50), consisting of a shaft with crank and clamping device on one base-board r>2.198. Torsional Force Model, Friedr. C. G. Muller's (M. T., Fig. 25) 52,199. Spring Balance (Jolly's), Figure (M. P. I, Fig. 330 [322]), with three different spiral springs, with metal stand, scale backed with silvered glass for avoiding parallax in reading £ s. d. 5.10.0 6.10.0 52,200. Simple Spring Balance for stress, Figure •VJ.201. - - idem, with stand and balance pan, as suggested by Kleiber, Figure. . .~>L'.202. Spring Balance (Friedr. C. G. Muller's), Figure, going up to 300 g, with two marks for showing maximum and minimum load (M. P., Fig. 7 and 74) . J 1.10.0 0.15.0 3. 0.0 0. 5.0 0.10.0 1. 5.0 f'l. 3321, 691, 4181. 310 Molecular Effects of Solids. 52 203. 1 : 4. 52 205. 1 : 6. 52.203. Universal Spring Balance with large dial, Kleiber's, Figure (Fr. phys. Techn. I, 2, Figs. 2062, 2103, 2160, 2445; Ztschr. f. d. phys. u. chem. U. 17, 1904, p. 141) . . . Two balances are necessary for a number of experiments and should be ordered if opportunity arises. 52.204. Model of a Spring Balance, so called Kitchen Balance, with plainly visible mechanism and scale under glass, Figure 52.205. Spring Balance, Figure, with range 0 — 5 kg and 0 — 25 kg, nickelled; can also be used as a dynamometer for tensile forces 52.206. Dynamometer (Spring Balance) for tensile forces, as suggested by Hesehus, Figure, with scale from 0 — 15 kg (Gan.-Man. Figs. 6 and 7) 52.207. Dynamometer, Poncelet's, for 25 kg, Figure 52.208. Dynamometer with balance pan, of brass, nickelled 52.209. Dynamometer with stirrup and handle, with pointer, Figure, scale 0 — 250 kg . 52.210. Spring Balance for Compression (M. P. I, Fig. 332) 52.211. Dynamometer for Compression, round scale, for 0 — 60 kg, with adjustable pointer, Figure 52.212. Dynamometer (Spring Balance) for Compression and Extension, F i g u r e, scale from 0 — 250 kg, with adjustable pointer Tin- extension hooks are not inclmled in the illustration. .">:.', LM3. Dynamometer for Compression (to .'? kg) and extension to 25 kg (on stand), Figs. A and B, with three hooked weights Cl. Siitio. fin-,, r.'.i WJ. £ s. d. 1. 6.0 1. 5.0 0. 5.0 0.15.0 3. O.o 0.15.0 3. 0.0 1.12.0 2. 0.0 2. 5.0 2. 15. 0 Xo r,2219. Dynamometers (Spring Balances), Resistance, Expansion. 311 52209. 1 : 10. 52 212. 1 : 5. 52 213 A. 1:6. 52 213 B. 1:6. 52,215. 6 Pieces of Wire, with lugs, for breaking tests, as suggested by Friedr. C. G. Miiller £ s. d. (M. T., Pigs. 31 and 3) | 0.10.0 Portable gallows No. 51,152, the indicating cylinder No. 51,452, balance pan No. 52,216 and one set of weights Nos. 51,676 — 51,684 are necessary for the experiments. 52,216. Balance Pan for heavy load (M. T., Fig. 3), see Figure 52,221 .">2.217. Viscosity Test Pieces for hammering out; bars of lead, brass, wrought iron, zinc, cast iron, wood and glass (M. T., p. 49), 3 pieces of each, 50 mm long, 10 mm thick . . 52,218. Sheet Iron Strip for Determining Elastic Limit, Viscosity and Strength (M. T., p. 49) . U-shaped Bar for Demonstrating Expansion and Jolting, Figure (M. T., Fig. 32) 0. 6.0 0. 8.0 0. 5.0 0. 2.0 Cl. 5525, 695, 5116, r,:il. 3640, 3641. 312 Models of Machine Elements, Machine Parts and Machines. \n. .".'_» -2'2 I - arte-aeala. ErlirUr drj>un-l«. Srnlr DarhBrrithaupt 52 221, 51 452, 52 216, 51 676 — 51 631, 51 121. 1 : 14. 52227. 1:3. 52 228. 1 : 9. 52230. 1:9. 52 232. 1 : 8. 52.221. Arrangement for Elasticity, Expansion and Breaking Tests, as suggested by Friedr. • £ s d. C. G. Miiller, for fitting to the lecture table, consisting of 1 screw clamp for securing the test wires and 1 guide pulley, also 6 test wires 1. 0.0 The following are also necessary for the experiments: indicating cylinder No. 51,452, balance pan No. 52,216, 1 set of weights Nos. 51,676 — 51,681 and 1 American screw clamp No. 51,121. For measuring the expansion the test wire is simply laid over the axis of the indicating cylinder and not slung round it. 52.222. Batavian Glass Drops per dozen 0. 0.6 52.223. Bologna Flasks per 10 0. 1.0 52.224. Press (Reusch's), for producing sliding surfaces in calc-spar and rock salt, with pre- paration 1. 5.0 52.225. Pressed and Unpressed Preparations, singly 2 s. 6 d. to 0. 4. 0 52.226. Press (Baumhauer's) for producing the calc-spar doublets 1. 4.0 52.227. Hardness Scale (Mohr's), Figure, with large stone specimens, porcelain slab, writing diamond and bar magnet, in wood box 0.18.0 Models of Machine Elements and Parts and of complete Machines. Machine Elements and Simple Machines. 52.228. Prism with its hollow mould, Figure, of wood, sliding on each other 0. 1<>. u 52,22!». Shoe Guide, Figure, of wood 0. 12.0 :>2.2.'50. Journal with bearing, Figure, of wood, with 2 turning surfaces fitting in each other ' | 0.12.0 52.231. Circular Groove with Circular Slot (incomplete journal), of wood 0.18.0 52.232. Bolt and Nut, Figure, of wood 0.18.0 ci. :.T.M. 3i:>-'. 514, M:.. 614, 'i No. 52211. Machine Elements, Simple Machines, Screw Gears. 313 52 237. 1 : 6. 52 238. 1 : 6. 52 239. 1 : 0. 52 241. 1 : 6. 52 240. 1 : 6. r>2.233. Triangular Screw Thread with Nut cut through, Figure, of wood ..... 52,234. Square Screw Thead, with Nut cut through, Figure, of wood 0. 3. 0 £ s. d. 0. 2.6 52,235. Model of Screw with 4 threads of different shape and pitch, without nuts, of metal, Figure 52,236. Simple Machines, Figure, Wedge, Windlass, Capstan, Toothed Gearing with fly- wheel, Worm Gearing and Screw Jack, mounted on one baseboard. Gearing with Screws, Cranks, Links, Rods, Joints and Discs. 52,237. Fixed Nut with Rotary Screw Spindle, Figure, with angular, accurately turned thread, constructed entirely in iron :>-. 238. Fixed Screw Spindle, with Rotary Progressive Nut, Figure 1.10.0 4.15.0 1. 0.0 1. 4.0 52.239. Screw Spindle, rotary, resting immovably in its bearings, with straight guided, pro- gressive nut, Figure 1.10.0 52.240. Rotary Nut, incapable of lateral movement, with straight guided, progressive screw spindle, Figure 52,241. Screw with Right-and-Left-Handed Thread, Figure, with nuts 1.10.0 2.10.0 Apparatus for showing the formation and mode of action of the screw, see No. ~>l,i)05 — 51,910, p. 273. C1.518.M9, 8788, 621,8787, 5805, 3788, 520, 3789. 314 Models of Machine Elements, Machine Parts and Machines. Nn. 52244. 1:10. 52 248. 1 : 8. 52 243. 1 : 6. 52 250. 1 : 6. 52 252. 1 : 4. 52 253. 1 : 5. 52.242. Screw with two Threads of Different Pitch, with nuts (differential gear) 52.243. Screw Thread with Ratchet Brace, of metal, Figure (M. P. I, Fig. 275 [272]) 52.244. Screw Press, of wood, Figure 52.245. Quadrilateral Crank Gear, with a rotating and an oscillating crank 52.246. Rotating Double Crank 52.247. Oscillating Double Crank 52.248. Parallel Crank, Figure 52.249. Counter-motion Anti-parallel Cranks 52.250. Anti-parallel Cranks, working in same direction, Figure 52.251. Equilateral Crank Gear (Galloway's) . A crank rectangle, in which the two adjacent sides are equal, and the opposite pairs of sides differ in length. 52.252. Crank Shaft, Figure, of metal 52.253. Oscillating Thrust Crank, Driving Wheel with Connecting Rod, with cross head and guide, F i g u r e, of metal 52.254. Oscillating Slot and Crank, Connecting Eod in the form of a piston rod, cylinder oscillating This mechanism is also employed in the sectional model of an oscillating cylinder of steam engine to be mentioned later. n. 53%. r..i.w. 144, :••-•! £ s. <1. 2.10.0 1.16.0 0.10.0 4. 0.0 4. 0.0 4. 0.0 4. 0.0 4. 0.0 4. 0.0 4. 0.0 2.10.0 5. 0.0 5. 0.0 No. 52 261. Screw, Crank~and Slot Gears. 315 52 255. 1 : 6. 52 256. 1 : 6. 52 258. 1 : 9. MAX KOHL CHEMNITZ 52 259. 1 : 6. H '. N 52 260. 1 : 8. 52 261. 1 : 4. 52.255. Rotating Crank and Slot, Figure, changes uniform rotation into unsymmetrical, periodic rotation • The axes of the crank and slot are placed so close to each other that the slot .rotates. 52.256. Crank and Slot, the slot arranged to rotate, Figure This gear is similar to the previous one; the axes of the crank and slot are, however, placed at such a distance apart that the slot can no longer rotate but only oscillate. 52.257. Equal-limb Rotating Crank and Slot 52.258. Oscillating Cross Slot, for versed sine motion, Figure 52.259. Rotating Cross Slot, Figure 52.260. Oldham's Coupling, Figure, serving as organ of transmission between two parallel axes A practical application of the rotating cross slot. The two axes have the same angular velocity. 52.261. Model of the Bent Lever, Figure (Fr. phys. Techn. I, Figs. 124—126; M. P. I, Figs. 280 — 282); testing of same by suspending weights. Price without weights . . Cl. 526, 3626, 5343, 528, 529, 4866. £ s. d. 4. 0.0 4. 0.0 4. 0.0 4. 0.0 4. 0.0 4. 0.0 3. 0.0 316 Models of Machine Elements, Machine Parts and Machines. No. .V.'26-> — 52232. 1:12. 52 263. 1 : 6. 52 264. 1 : 6. 52 266. 1 : 7. 52.262. Peaucellier's Guide, Figure, for transforming a circular into a straight motion 52.263. Watt's Parallelogramm, Figure, of wood and metal 52.264. Beam for Steam Engines with counter-guide, Figure 52.265. Beam without Rotating Axis 52.266. Stephenson's Link, Figure, with section through a steam engine cylinder with slide valve, of iron (Gan.-Man. Fig. 569) 52.267. Gooch's Link, of iron 52.268. Model Table for demonstrating the Static Equilibrium Conditions of the Centrifugal Governor, as suggested by Prof. Eugen Meyer, Figure (Ztschr. d. V. d. I., 1909, pp. 1301 et seq., No. 2, and text-sheet 13, Figs. 4 — 7) The model shows half of a centrifugal governor. At the points of support of the pendulum a, the rod b and the bush c forces can be applied instead of the bearings. The model serves for deter- mining the quantity of that horizontally directed force 0 which maintains the equilibrium in the forces Q (half the weight of the socket) and G (weight of the governor balls), this force C acting on the centre of the balls. 52.269. Conical Crank Rectangle, coupled conical cranks 52. 2 70. Conical Thrust Crank Chain, connecting rod and guides running on section of cylinder 52.271. Rectangular Cross Sprocket Chain, simultaneous motion of a sphere about two axes 52.272. Cardan's Coupling for transmitting a rotary motion at any angle, of metal . . . r>i>, 273. - - idem, with graduations on the axes and on the base-plate The angular velocities of the two axes are unequal. In order to show the lead and lag of the driven shaft, in front of and behind the driving shaft a dial graduated in degree.- is fastened in front of one each fixed pointer, and graduations are put on the base-plate on which the angular position of the two nlative axes can he read off. The degree of lead or lag of the axes relatively to each other depends on the angle which the directions of the axes form with each other. If ..< and ..>, are the anghs of rotation measured from I lie same position of rest, of the driving and driven shafts respeo ts a>i tively, and « the angle of direction of both, then ' DOSa. £ s. d. 6. 0.0 1.16.0 4. O.(t 4. 0.0 12. 0.0 12. 0.0 6.15.0 (i. 0.0 6. 0.0 0. 0.0 1. :>.(> 2. 10.0 Models of Strain Kngines and Steam Knginc Tails. see section on Heat. Cl. 57N7. r.:n, 11:11. :.3a Rod, Joint and Disc Gears. 317 52 276. 1 : 7. 52 278. 1 : 7. 52.274. Cardanic Double Coupling, Figure, for the uniform transmission of motion at any angle or on a parallel axis, "with degree graduation on the axes and on the base- plate The two cross joints of this model are equally placed. The dissymmetry of the transmission "t motion of the single cross joint is obviated by the use of the two equally placed cross joints when tin- two external axes opposite the centre axes form the same angle either whether they form twice this angle of inclination among themselves or whether they are parallel. 52.275. Goubet's Coupling (Double Universal Coupling), Figure, with sleeve, for two intersecting axes, with graduations and pointers The ratio of rotational speeds of the two axes is constant. 512,1276. Clemens' Coupling, Figure, with ball and socket joints for two intersecting axes The ratio of rotation of the two axes is constant. Oldham's Coupling see No. 52,260, p. 315. 52,277. Excentric Slot . £ 8. d. 7. 0.0 6.10.0 7. 0.0 4. 0.0 52,278. Excentric Drive with guides, Figure 4. 0. 0 Cl. 5632, 3959, 533. 535, 536, 5347. 318 Models of Machine Elements, Machine Parts and Machines. No. .-,iL'7» - 52279. 1:5. 52 283. 1 : 6. 52 284. 1 : 7. 52 285. 1 : 7. 52286. 1:5. 52.279. Simple Excentric, the excentricity adjustable, Figure, of metal 52.280. - - i d e m, adjustable by toothed wheels 52.281. Excentric with Slot for versed sine motion 52.282. Double Excentric with reverse motion, for forward, and backward running of loco- motive, Figure, of metal 52.283. Cam Disc, Figure, of wood 52.284. Cam Motion (versed sine motion), Figure 52.285. Archimedian Spiral Disc, Figure, for uniform reciprocating motion 52.286. Arc Triangle, Figure, for intermittent motion 52.287. - - idem, smaller 52.288. Double Heart-Shaped Slot for uniform motion of rods For two up and down strokes during one revolution of the heart-shaped cam. Tooth and Worm Gears. 52.289. Model Table, demonstrating the formation of the Cycloid, the rolling curve of the circle on a straight line 52.290. -- idem, the formation of the Epicycloid (circle rolled on the circle) 52.291. -- idem, the formation of the Hypocycloid (circle described in the circle) . . . 52.292. - - idem, the formation of the Involute, Figure £ 8. (1. 2.15.0 7. ().(» 6. O.o 5. 0.0 0.1S.O 2.10.0 4. O.o 4. O.o 2.1.ri.o 4.10.0 16.0 L6.0 16.0 Ki.O Cl. 53-<. :.:i7. :ts7i, 539, 54". .Ml No 52304. Disc Gears, Toothed Gears. 319 . MAX KCHIL CHEMNITZ 52 292. 1 : 7. 52295. 1:10. 52296. 1 : 10. 52 300. 1 : 10. 52 301. 1 : 5. 52 302. 1 : 6. 52,293. Model Table of a Cycloidal Gear System, containing a movable model and the precise I £ s. d. 2. 10. 0 constructional drawing of the gear (ratchet with toothed wheel), cf. Figure 52 295 52.294. - - idem, Epicycloidal Gear System of Spur Wheels 52.295. - - idem, Hypocycloidal Gear System, with internal toothed wheels, Figure . 52.296. - - idem, Involute Gear System of Spur Wheels, Figure 52.297. - - idem, Rectilinear Face Toothing for wheels with external contact .... 52.298. - - i d e m, Double Pin Gearing with four toothed drive 52.299. - - idem, Involute System for Back and Pinion 52.300. - - idem, General Gear System of Spur Wheels, Figure 52.301. Two Spur Wheels with external topth-contact, Figure, of metal The direction of motion of the two pinions is opposite. 52.302. Spur Wheel Sector and Small Spur Wheel, Figure, with cycloidal profile . . 52.303. - - idem, with involute profile 52.304. — idem, with rectilinear face profile 2.10.0 2.10.0 2. 10. 0 2.10.0 2.10.0 2.10.0 3. 0.0 2. 0.0 3.10.0 3.10.0 3.10.0 Cl. 3627, lilias, 3629, 3t>30, 542, 3310. 320 Models of Machine Elements, Machine Parts and Machines. 52 311. 1 : 5. 52 312. 1 : 6. 52.305. Large Spur Wheel Sector with Small Spur Wheel, Figure, very largo pattern, for £ demonstrating the Boiling of the Tooth-profiles on each other, with cycloidal profile . 5.1(>.(> 52.306. - - i d e in, with involute profile 5. 10. 0 52.307. Two Toothed Wheels, with an intermediate wheel, for transmission without changing direction or rotation 4. 0.0 52.308. Two Toothed Wheels with two intermediate wheels, for transforming into a reverse direction of rotation 4.10.0 52.309. Wheel Suspension with five toothed wheels, Figure, for connecting up two parallel axes of variable distance 6. 0. 0 52.310. Internal Toothed Wheel and Spur Wheel, Figure, of metal 2. lo.o The direction of motion of the two wheels is the same. As a number of teeth are always in contact at the same time greater power can be transmitted by this gear than with spur gearing pure and simple. .">:.'. .'ill. Rack with Spur Wheel Motion, Figure, of metal 52,312. Universal Wheel Apparatus (Kmsmann's), Figure (Fr. phys. Techn. I, 2, Fig. 2042 [I, Fig. 84]; Ztschr. f. d. phys. u. chem. U. 2, 1885, p. 5) Four different kinds of toothed wheels are used on the apparatus, viz., the. spur wheel, the hevel wheel, the crown wheel and the lantern wheel. The crank can be placed on either the centre or lower horizontal axis, and the ratio of gearing in the former ease on the upper vertical axis is 1 : 30, and in the latter' ease the ratio is 1 : 60. 2.ir..o 4. 0.0 r>2,;>i3. Mangle Gear, of wood, hn-ge model 52,314. — idem, Figure, of metal . 3. 0.0 •2. 2.0 54.-.. :,:.'•. f,!4. 546. No. ~.~2i. Toothed Gearing. 321 52 314. 1 : 4. 52313. 1:6. 52 317. 1 : 7. 52 322. 1 : 9. 52 324. 1 : 5. 52 323. 1 : 4. 52,315. Mangle Gear with external teeth: a movable model and accurate constructional drawing of the gearing 52.316. Mangle Gear, rectangular: Crown Wheel with lantern wheels, Figure, of metal 52.317. Mangle Gear with double lantern wheel drive and internal contact with 4 -toothed channel cross-piece, Figure t The transmission of motion of this toothed gearing is very smooth and uniform. The ratio of t | gearing is 1:2, the lantern wheels being provided with small rollers. 52,318. - - i d e m, with 3-wheeled drive and 6-toothed channel cross-piece 52 319. Two Cam-shaped Cogs with Excentric Axes for periodic motions 52.320. Two Toothed Wheels with Excentric Axes for alternately producing accelerated and retarded motions 52.321. Two Cam-shaped Toothed Wheels, of different shape 52.322. Two Congruent Elliptical Toothed Wheels, Figure . The model shows the conversion of a uniform rotation into a periodically varying one. For facilitating the drive a spur gearing is fitted. The axes of rotation of the elliptical wheel each pass through a focus of the ellipses. 52.323. Two Toothed Wheels shaped according to the logarithmic spiral, Figure . . . . ">2,324. Mitre Gearing, small, Figure £ s. d. 2.14.0 5. 0.0 4. 0. 0 5.10.0 7. 10. 0 6. 0. 0 10. 0.0 6. 0.0 10. 0.0 1. 0. 0 Cl. 547, 527, 549, MH- 6355, 3632. 01 21 322 Models of Machine Elements, Machine Parts and Machines. 52 325. 1 : 4. 52326. 1:6. 52 329. 1 : 6. 52 327. 1 = 6. 52 331. 1 : 6. 52332. 1:10. 52,325. Two Bevel Wheels, the axes of which intersect at right singles, Figure, of metal £ s. 2,330. Two Pairs of Wheels with Screw Toothing, 1 pair for right hand and 1 pair for left hand motion, driven by 1 shaft The axes of ihe screw wheels of each pair are perpendicular to each other, the driven wheels rotating in opposite directions. 52,331. Two Wheels with Screw Toothing, with inclining axes, Figure 52.332. Model Table of the Worm, with Worm-Wheel, Figure, comprising a movable model and constructional drawing 52.333. Worm and Wheel, very neatly constructed of wood, Figure 52.334. --idem, of metal, simple, with V-thread, wheel with flat faced teeth "•2,335. - - idem, with flat, double thread; wheel with concave teeth, Figure . . . . 52.336. Worm with Square Thread, large; brass wheel 10 cm diameter with concave teeth 52.337. - - idem, with V-thread, large, brass worm wheel with concave teeth 52.338. Double-Thread Worm, large, Figure 5i'.:j39. Screw Thread with Worm, in cylindrical casing, Figure 52.. '540. Hyperbolical Toothed Wheels with inclining axes, Figure 01. 3790, 554, 555, 556, 3633 £ S. d. 12. 0.0 6. 0.0 3. 4.0 0.12.0 1. 0.0 1.16.0 3. 0.0 3. 0.0 3. 0.0 2.10.0 12. 0.0 21* 324 Models of Machine Elements, Machine Parts and Machines. No. 52341 52 341. 1 : 6. 52 342. 1 : 5. 52344. 1:5. 52 346. 1 : 8. 52.341. Spiral Wheel with Toothed Wheel, Figure The two axes are perpendicular to each other and intersect (without meeting one another). 52.342. Counting Mechanism with Differential Wheels, Figure 52.343. Reversing Gear with Spur Wheels 52.344. Differential Epicycloidal Gear with Spur Wheels, Figure, for the addition and subtraction of two rotary motions The resultant motion can be determined with the aid of a graduation and pointer. 52.345. Simple Epicycloidal Gear with 2 wheels, for simultaneous rotation of the body about two parallel axes, for proving that this rotation is equivalent to the rolling motion of a cylinder on the jacket of a fixed cylinder 52,340. Cycloidal Gear with Bevel Wheels (Taudin-Chabot's), Figure, quite tree from iron parts 52.347. Lahire Guides, Figure, for versed sine motion 52.348. Guides with 2 Cranks, coupled with each other by congruent toothed wheels . 52.349. Planet Wheels (Watt's), Figure 52.350. - - i d c in, with counterpoise and fly-wheel 52,351. Rack Motion, Guided Plate with groove, Toothed Wheel and Endless Rack; a toothed piston with movable axis which engages alternately in both sides of the ruck, for con- verting a continuous rotary motion into a uniform reciprocating motion rc'..';.")2. Rack Motion, partially Toothed Wheel and double Toothed Rack in slotted guide, for reciprocating motion £ s. d. 6. 0.0 5. I). (! 10. 0. 0 7. 10. 0 6. 5. 0 .">. Id. I) 6. 0. d 7.10. 0 6. 0. 0 7.1(>. o 10. 0. d 8.10.0 i I :..-,7, 559. 560, 4131! Ko. 52360. Toothed Gears. 325 52347. 1 = 7. 52 349. 1 : 9. 52 357. 1 : 7. 52 360. 1 : 8. ">L',:;.Vi. Connecting Rod with Guides, Toothed Wheel and Toothed Racks, for doubling the stroke of alternating motion »2,354. Interference Mechanism, for the addition and subtraction of 2 oscillating versed sine motions, for explaining interference phenomena Two toothed wheels, one having 66 and the other 67 teeth, are mounted on parallel axes and fitted with cranks and connecting rods joined up to the same beam. The latter is fixed to the recti- lineally reciprocating rod. 32,355. Masked Rotating Slot and Crank This mechanism corresponds in its action to the rotating slot and crank No. 52,255; the motion is, however, transmitted by toothed wheels instead of by a slot and crank. >2,3r>f>. Toothed Gear for Oscillating Movement, Curved Back and partially Toothed Wheel ">2.357. Mangle Wheel, Figure, for reciprocal rotation at constant speed >2,35H. Intermittent Wheel with External and Internal Teeth, for reciprocal rotation at dif- ferent speeds; the teeth traverse each other in two places by small semi-circles. . . >L.'..',5!i. Reversing Gear, with Bevel Wheels )2,36<>. Differential Epicycloidal Gear with Bevel Wheels, F i g u r e, for the addition and subtraction of two rotary motions The resultant motion can be followed by a pointer rotating in front of a circular graduation. £ s. <1. 8. 10. 0 10. 0.0 7. 10. 0 8. 0.0 6. 0.0 12. 10. 0 13. 0.0 7.10.0 (I. !>«!, 562, 563, 3634. 326 Models of Machine Elements, Machine Parts and Machines. No. .V23I11 52361. 1:7. 52 365. 1 : 7. 52 371. 1 : 4. 52 373. 1 : 6. 52.361. Epicycloidal Gear with Bevel Wheels, Figure, for demonstrating the simultaneous £ * •' rotation of a sphere about two intersecting axes j 7. 10. o The model shows the simultaneous rotation of a sphere, about two intersecting axes, also, the fact that this rotation is equivalent to the rolling of a cone on a fixed cone. The sphere in tins system of wheels rotates about a momentary axis which is continually altering its position with refe- rence to the sphere. 52.362. Turning Gear with partially Toothed Bevel Wheels 8. o. o 52.363. Single-tooth Wheel and Star Wheel (Maltese Cross) 6. lo. o 52.364. Counting Mechanism with single Tooth Wheels 10. 0. o 52.365. Ratchet Gear, working with half teeth, Figure 4.10. u 52.366. Ratchet Gear, with continuous motion 3. 10. o 52.367. Switch for Machine Tools 6.10.0 Couplings, Connecting and Disconnecting Devices. 52.368. Toothed Wheel connecting and disconnecting arrangement for two parallel axes, with auxiliary wheel 6.10. 0 52.369. Coupling with Friction Cone 7.10. o 52.370. Coupling with Brake and Claws, for engaging slowly and smoothly by friction and firmly coupling by means of the claws "• !"• (l 52.371. Coupling with Friction Cone and Claws, F i g u i e. for engaging slowly and smoothly by friction and obtaining a firm coupling by means of the claws 9.10.0 .")•_',. '.72. Coupling with Brake and Planet Wheel, for smoothly engaging, with spur wheels . lo. lo. o .">!'. .'{73. Change Gear with Bevel Wheels and Claw Coupling, Figure, for changing the direction of rotation 9. lo. o 52,374. Clutch Engager with Screw for toothed wheels. Figure 6. o. 0 .">_'.. '575. Engaging and Disengaging Arrangement for toothed wheels by means of an inter- mediate wheel . 13. o. o il. :,<• N.I. Toothed Gears, Couplings, Engaging and Disengaging Gears. 327 52 374. 1 : 6. 52 376. 1 : 5. 52 379. 1 .- 6. 52.376. Engaging Gear with Brake, Figure t / B The belt pulley visible to the left of the illustration and connected with the driving mechanism '• is only moved by the crank fitted at the right hand side when the brake is put on, i. e., when the brake | pulley is held fast. So long as the brake remains loose the belt pulley remains at rest consequent on ^ the resistance of the driving machine, and the brake pulley rotates with its driving mechanism. The I action of engaging can be carried out smoothly by carefully manipulating the brake. The brake (con- trary to the illustration) is applied by means of a handwheel and screw; it can therefore be put on iu slowly and be left on at any position affording a more or less tight grip. 52.377. Engaging Gear for any Direction of Rotation, with spur wheels and pulley stand, triple broad belt pulley with crank, moving fork for engaging, and driving belt . . 9. 0. 0 52.378. Engaging Gear for engaging in any Direction of Eotation by means of bevel wheels, with pulley stand, triple broad belt pulley with crank, moving fork for engaging, and with driving belt + 10. 0. 0 The engaging gear consist of three pulleys fitted on the same axis. The no-load pulley is in the centre; one pulley for full load is fixed on the axis, the other pulley being connected to the last by a spur wheel gear in such manner that it always rotates in the opposite direction. According as the belt is thrown on to one or other of the two outer pulleys, the shaft runs in either direction. 52.379. - - idem, with Intermediate Gearing, in order to obtain another velocity in the one direction of rotation . |12. 0. 0 £ s. d. 9. 0. 0 52.380. Band Brake 52.381. Wedge Friction Wheels 8. 0.0 3.12.0 Cl. 569, 3635, 5777. 328 Models of Machine Elements, Machine Parts and Machines. 52 382. 1 : 5. 52383. 1 : .->. 52 386. 1 : 5. 52 389. 1 : 5. Transmission of Motion by Belt, Cord and Chain. 52.382. Cord Drive, Figure, with metal pulleys 1. 4. 0 52.383. Step Cone Transmission by Belt, for two parallel axes, Figure 3.10.0 52.384. Cone Pulley Drive with automatically fed belt guide for producing an unsymmetrical rotary motion 10. o. o 52.385. -- idem, with curvilateral cones for uniformly accelerated motion 14. o. o 52.386. Belt Gear disengaged by a loose pulley, for two parallel axes, Figure .... 4. o. o .'>.!. 387. Belt Gear for two axes which intersect 6. 5. 0 One of the belt pulleys, in addition to rotating about its own axis, can rotate about one which is perpendicular to the same and to the axis of the other pulley. 52,388. Belt Gear for two axes inclined towards each other, with two belt pulleys lying in one plane, one of these being connected with its axes by a Hook joint 7. 10. 0 ."»L'.3SJ». Belt Transmission with two Belt Pulleys with variable angles, F i g u r e, with guide pulley 5. 0. 0 - 52,390. Transmission by Cylindrical Spring between two axes in any positions 3.10.0 .">.!. :>!•!. Gall Chain Transmission for two parallel axes, Figure 3. lo. u Hoisting and Transporting Machines. :.L'..;'.)2. Simple Windlass, of wood o. lo. o .V_'.3<»3. Simple Windlass, Figure, of metal o. is. o For Models of Tackle, *<•'• No*. .->i.sr>id — f. p. 260, 51,894 — 51,899, p. 271, and No. :>n.llii. p. 21. . . s, Xn. .V-' inn. Pliable Chains. Hoisting and Transporting Machines. 329 52 391. 1 : 5. 52 393. 1 : 4. 52395. 1:8. •'•"MmBHBSBi:.... 52 396. 1 : 5. 52 397. 1 : 6. 52398. 1:7. 52 399. 1 : 4. ] £ s. d. 52.394. Windlass with Crank, of wood ........................ 0. 16. 0 52.395. Differential Windlass, Figure, of wood (M. P. I, Fig. 242 [237]) ....... ; 1. 0. 0 52.396. Differential Windlass, Figure, of metal . . . . .............. 1.14.0 52.::97. Pair of Spur Wheels with Weights, on stand, Figure, for explaining the windlass j. 14. 0 52,398. Windlass with simple Toothed Gearing, Figure, of wood ........... 0. 18. 0 52,:i«M». Windlass with Toothed Wheel and Gearing, Figure, of metal (M. P. I, Fig. 245 [239]) 2. 0. 0 52.400. -- idem, of metal, with brake pulley, brake band, lever and catch ..... . 6. (t. o 3311, 578, 3308, 579, 580. 330 Models of Machine Elements, Machine Parts and Machines. i>. .M> Kll 52 401. 1 : 7. 52 402. 1 : 8. 52 405. 1 : 4. 52 408. 1 : 9. 52.401. Windlass with Double Gearing, Figure, with brake pulley, brake band and lever; £ s. . 1X87, .'.-I No. 52421. Models of Hoisting and Transporting Machines. 331 52 411. 1 : 7. 52413. 1 : 10. .-.2.412. 52,413. :. 2.414. .".-'.415. .-.2.416. 52,417. ."•2,418. 52,419. .".-'.420. ."•-'.421. 52414. 1:9. Crane without Strut Crane with Variable Jib, Figure. . . . Wall Crane, constructed of iron, Figure 52 416. 1 : 8. £ 8. d. 10. 0.0 12. 0. 0 12. 0.0 Shore Turning Crane, with fixed rotary axis 15. 0. 0 Shore Turning Crane with a Rotary Axis sunk under the bottom, Figure . . . 15. 0. 0 Shore Turning Crane with Sheet Iron Staging 21.10.0 Turning Crane, rotary on wheels 17.10.0 Travelling Crane, of iron 21.0.0 Traverser with Pit 17. 10. 0 Turntable . 17. H>. o fl. 4100, 585, 586, 363H. 332 Models of Machine Elements, Machine Parts and Machines. 52424. 1:8. 52 425. 1 : 7. 52 423. 1 : 7. 52427. 1:5. 5" 4"" Pile Driver Figure of wood and metal . £ 1 s. • > d. 0 .">". 12.'! . Straight Pile Driver, Figure, of wood, finest construction (1 (t :,2.421 5'' 4 "5 Dynamometers. . Brake Dynamometer (Prom's Friction Brake). F i g u re (of. M. I*. I, Fig. :C>1 [:W7]) - - i d e in different pattern F i |r u r e •_> 3 (1. (1 (» (I •V l"(i Friction Brake as suo^ested bv Fried r (' (1 Miiller (M T, Fi 1.77.".— r. 1.77(1, p. 252. cl. :.T2. :.-?. 5T2", (84 No. M1 i::::. Pile Drivers, Brake Dynamometers, Clock Movements. 333 52428. 1:10. 52430. 1:12. 52431. 1:3. 52433. 1:10. Clock Movements. 52,427. Model of a Pendulum Escapement, Figure, with detachable escapement; swing 1 o second; can also be used as a chronometer 52,428. Model of a Clock, with complete movement and perforated dial 20 cm diameter, Figure 52,429. - - idem, with electric minute contact, see No. 51,704, for connecting up with an electric dial 52,430. Model of a Clock from an old specimen dating back to the year 1640, Figure, of wood, iron and stone A stone is used for the weight; the hook has a circular motion and releases the escape wheel, whose teeth lie in the horizontal plane. 52,131. Model of an Anchor Escapement, with spring drive, Figure 52,432. Model of a Cylindrical Escapement . 52.133. Model of a Turret Clock Movement, Figure (Fr. phys. Techn. I, 2, Fig. 3286) £ s. ,1. 1. 0. 0 2.10.0 3. 0.0 0.16.0 3. 4. 0 3. 10. 0 9. 0.0 Models of Water- Wheels, Turbines, Valves, Steam Cylinders, ci. STB-, ese, Steam Engines, etc. are listed iurther on in this Catalogue. 637< 502°- 334 Equilibrium, Motion and Molecular Effects of Liquids. No. 52434- 52434. 1:10. 52435. 1:10. Equilibrium, Motion and Molecular Effects of Liquids. .~>L'.134. Universal Hydrostatic Apparatus, Figure, suitable for a large number of experi- £ * l] ments in the Mechanics of Liquids and Gases; can be used in a horizontal and vertical position 10. 0. 0 The apparatus can be used :( 1 ) for the propagation of pressure of liquids and gases in all directions ; (2) as a hydraulic press; (3) for buoyancy experiments; (4) as a Pascal apparatus; (5) as communi- cating tubes; (6) with capillary tubes; (7) as well-springs; (8) for outflow experiments; (9) for decrease of pressure in cylindrical tubes; (10) as Segner's water wheel; (11) for the hydraulic ram; (12) as Heron's ball; (13) Cartesian divrr. Complete description and directions for use on application. ~>L',135. -- idem, in box, Figure 52,43(i. Apparatus as No. 52,434, but constructed half as large again 52,437. — i d e in, in box .">2.4:ts. Apparatus for showing Pressure Drop in Tubes of various widths, for use in conjunction with one of the universal hydrostatic apparatus Nos. 52,434 — 52,437 .->2,4.4f!i. Hartwich's Apparatus for the Hydrostatic Paradox (Ztschr. f. d. phys. n. chem. U. 16, 1903, p. ->7">) This apparatus ran also tic used in conjunction with I he universal hydrostatic apparatus. 11.10.0 14. 0.0 16.10.0 1. 0. 0 3. 0. 0 ( I. 723. 5530. No. 524.M. Universal Apparatus, Spirit Levels, Propagation of Pressure. 335 52 442. 1 : 3. 52452. 1:7. 52 453. 1 : 8. 52 454. 1 : 6. Equilibrium of Liquids. 52. 440. Tube Level Model (Weinhold's), Figure (W. D., Figs. 104 and 105 [93 and 94]), length 40 cm, with polished stand 0. 11. 0 52.441. - - idem, stand unpolished 0. 9. 0 52.442. Tube Level with metal base, Figure (W. and E. phys. Prakt., Fig. 12) ... 0. 7. 0 52.443. - - idem, smaller and simpler pattern, with iron base 0. 3. 0 52.444. Spirit Level in cast iron case, Figure, for perpendicular and horizontal surfaces, shafts, etc 0. 8. 0 Round Spirit Level, of brass, nickelled, Figure. List No. 52,445 52,446 52,447 52,448 Diameter mm 25 30 40 50 £ 0.3.6 0.4.6 0.5.0 0.5.6 52.449. Pressure Tube with Piston and Plugs, for showing the invariability in volume of liquids and the difference between liquids and gases (M. T., p. 95) 0. 2. 0 52.450. Apparatus for Propagation of Pressure, hollow brass sphere with fine holes and force pump placed on same, similar to Fig. 52,452 (W. D., Fig. 106 [95]), without pressure gauge 0.13.0 52.451. --idem, of glass (spherical squirt) 0. 3. 0 52.452. Apparatus for the Propagation of Pressure in Liquids and Gases, of brass, with Pressure j Gauges, Figure 1. 0. 0 52.453. --idem, on stand, Figure, with pressure gauges and stop-cock (Fr. phys. Techn. I, 2, Fig. 2692) 1. 16. 0 52.454. Brass Cube for Pressure Propagation, Figure, with six thin rubber membranes, as suggested by Browne, with 2 stop-cocks for leading in and taking off the water or air, on stand (Fr. phys. Techn. I, 2, Fig. 2333) 2. 0. 0 £ s. d. Cl. 701, 703, 702. 704. 70S, 3642, 706. 336 Equilibrium, Motion and Molecular Effects of Liquids. X" :.2) 52 456. 1 : 6. 52455. 1:5. 52 458. 1 : 6. 52 459. 1 : 12. £ s. ,1. 52.455. Apparatus for demonstrating the Distribution of Pressure in Long Tubes, Figure o. Hi. o Two communicating glass cylinders, qne being closed by a rubber membrane and the other by a ' rubber plug, have each a closed pressure gauge with rubber tubing (Piezometer). When pressure is applied to the membrane the coloured liquids in the two gauges rise to the same height. 52.456. Wave Tube (Maxwell's), Figure, for explaining the formation of the residuum, slow equalisation of pressure; can be used as an analogue for the charge and discharge of a condenser (Fr. phys. Teehn. I, 2, Fig. 2392) ± Id. o 52.457. Tube with closed Pressure Gauges, for pressure distribution, as suggested by Friedr. ('. (I. Miiller (M. T., Fig. 57) ' . . . . I. ."ii',-158. Hydrostatic Apparatus (I'ecknager.s), modified by Friedr. ('. (!. Miiller, Figure, for showing the distribution of pressure in liquids and the regularity of aetion on the area of the walls of vessels (Pascal's Law); the apparatus can be used also as a demon- stration model for the Hydraulic Press (Ztschr. f. d. phys. u. chem. U. 7, 1893/94, p. 7; M. T., Fig. 58) ' 3. ti. (I .'•:.'. l."i!>. Hydraulic Bellows, Figu re (W. 1)., p. 148 [127]), comprising rubber cushion with hose, funnel tube and supporting board, without weight and stand l.ll'. u A few litres (if water are tir>t poured into the tube, and the supporting board and a li."> — ~>0 kg weight are placed on the cushion, and the result shows that the weight i- raised by slowly filling with water. C I. 3324, 502:!, 3325, 3839. No. 52466. Propagation of Pressure. Hydraulic Presses. 337 52 461. 1 : 6. 52465. 1:4. 52 463. 1 : 7. 52466. 1:8. 52.460. Flat Sheet Iron Box, for storing the rubber cushion (W. D., p. 148) 52.461. Hydraulic Press, Figure (W. D., Fig. 107 [96]), massively constructed of iron and steel; valves fitted, so as to be detachable, in special valve chambers, giving 3000 kg pressure, with safety valve for 60 atmospheres The ram has a cross-section of 50 sq. cm; each atmosphere of pressure thus corresponds to a 50 kg pressure. The press has an efficiency of 60 ats., which is equivalent to 3000 kg pressure. • 52,462. - - idem, with Pressure Gauge 52.463. Hydraulic Press, of metal, for a pressure of 1500 kg, Figure 52.464. - - idem, with Pressure Gauge 52,465. Hydraulic Press with Glass Cylinder and visible valves, Figure, with safety valve for 25 Atm., for preventing bursting of the cylinder, for 500 kg pressure 52.466. - - idem, with Pressure Gauge, Figure Cl. 707, 709, 708, 5119. £ s. d. 0. 8.0 12. 0.0 14. 10. 0 8.10.0 11. 0.0 8. 0.0 10.10.0 22 338 Equilibrium of Liquids. No. 52 467 — 52 467. 1 : 7. 52468. 1:11. 52469. 1:13. 52.467. Hydraulic Press, Figure, with lever, arranged so as to be rotary, for moving same from any side; arranged for breaking wood rods, etc 52.468. Hydraulic Press for Compression and Lift, on wood stand, with safety valve, pressure gauge and hook for weights, Figure The press is mounted on a thick oak stand, is of the same type and efficiency as No. 52,461, and is intended to be used for showing the considerable loads which can be lifted by means of the press. 52.469. Hydraulic Press, for Compression, Lift and Extension, with iron frame, Figure, with safety valve and pressure gauge, suitable for strength tests The press has a massive iron frame and is fitted with two stout clamps for gripping wires, bands, etc. in elasticity experiments. Type and efficiency as in No. 52,461. Iron wire 7 mm in diameter can easily be broken in the press. 52.470. Model for explaining the Hydraulic Press, Figure, of glass in metal frame, lifting 100 g 52.471. — i d e m, without framework 52.472. --idem, as No. 52,470, Double Size, with mount and vessel 52.473. Rubber Vessel, for showing the Increase of Pressure downwards, Figure (W. D., Fig. 109 [98]), to be filled with mercury 52.474. Sheet Iron Cylinder with holes at different heights, Figure, for showing the in- crease of pressure downwards (W. D., Fig. 108 [97]) £ s. d. 6. 0.0 18.10.0 22. 10. 0 (I. 11'. 0 0. 3.6 1.10.0 0. 8.0 0. 6.0 Cli l'i'8. 710, 711. Hydraulic Presses. Increase o! Pressure. Bottom Pressure. 339 52473. 1:3. 52 476. 1 : 8. 52 479. 1 : 5. 52,475. Pressure-Increase Apparatus (Hartl's), Figure, for showing the internal pressure- relations in a liquid (Ztschr. f. d. phys. u. chem. U. 9, 1896, p. 120) The inferior part of a glass tubs is connected to a pressure-chamber shut by 2 membranes and turnable about a horizontal axis; in the superior part is fixed a manometer with scale. 5iM7i». Pressure-Increase Apparatus, after Hartl, with Pointer Reading, Figure (Ztschr. f. d. phys. u. chem. U. 8, 1895, p. 204), complete, with glass vessel and bridge . . The apparatus is used for showing (1) the increase of pressure downwards, (2) the independence of pressure on the inclination of the compressed surface towards the level, (3) the dependence of pres- sure on the density of the liquid. 52.477. Weighted Flask with Gauze Seal, after Eebenstorff, for depth measurement and demonstrating the inertia of water (Ztschr. f. d. phys. u. chem. U. 21, 1908, p. 107); capacity of flask, 100 ccm 52.478. Apparatus for proving Pascal's Law, after Friedr. C. G. Muller (M. T., Fig. 62 and 119), to be used as an analogon of the Ordinary Barometer and of the Siphon Barometer . The following are immersed in an upright cylinder filled with water: (1) 1 barometer tube open at both ends, this being placed under the water in a dish containing mercury; and (2) 1 unequal-limb hooked tube, which has to be filled with some mercury. 5L>.17!». Pascal's Apparatus, for showing that the pressure of liquids depends on their height and the surface of the bottom of the columns and not upon the capacities of the vessels, improved by Weinhold, Figure (W. D., Fig. 110 [99]), with 4 different tubes . . £ s. d. 1. 0. 0 3. 0. 0 0. 5. 0 0. 8. 0 3. 5. 0 Cl. 712, 713,714,715, 4123,5*31. 22* 340 Equilibrium of Liquids. No. 52481- *£Z 52481. 1:7. 52 482. 1 : 8. 52 483. 1 : 6. 52485. 1:7. 52.481. Pascal's Apparatus, for showing that the pressure of liquids depends on their height and the surface of the bottom of the columns and not upon the capacities of the vessels, Figure, with triple tube, the parts of which can be shut off by cocks, with 3 bottom pieces of different sizes 52.482. Pascal's Apparatus, for showing that the pressure of liquids depends on their height and the surface of the bottom of the columns and not upon the capacities of the vessels, Figure, can also be used as a Hydrostatic Balance, on board with levelling screws, with 3 tubes (M. P. I, Fig. 366 [360]) 52.483. Hartl's Apparatus, for showing that the pressure of liquids depends on their height and the surface of the bottom of the columns and not upon the capacities of the vessels, with 3 different tubes. The height scale is fitted to the movable piston so that the pressure-altitude and the magnitude of the pressure can be read off simultaneously (the latter on the pointer of the balance) 52.484. — idem, with 3 different rams, with plane, concave and convex surfaces . . . 52.485. Pellat's Apparatus, for showing that the pressure of liquids depends on their height and the surface of the bottom of the columns, Figure (Ztschr. f. d. phys. u. chem. TJ. 3, 1889/90, p. 55) The apparatus consists of a metal ring fitted to a massive stand, this ring being provided with a cock and a closing membrane acting on a pointer lever. An adjustable pointer is fitted to a vertical lever which permits of 3 differently shaped vessels, fitting the ring and pertaining to the apparatus, to be filled to the same level. The piston is packed with mercury. 52,487. Apparatus, for showing that the pressure of liquids depends on their height and the surface of the bottom of the columns and not upon the rapacities of the vessels, witli Spring Balance after Zahlbruckner, F i g u r e, with 3 different tubes The spring balance is contained in a brass tube with plain, two-coloured scale and pointer; a £ s. d. 2. 7. 0.0 4. 0.0 4.10.0 3. 0.0 5. 0.0 • •1. 717, 718, :;:;?-, 719. NIL .V>490. Bottom Pressure. Hydrostatic Paradox. 341 \ 52 487. 1 : 0. 52 488. 1 : 6. 52 489 A. 52 489 B. 52 489 C. 1:8. 5g 490. 1 : 7. special scale is provided for showing the level of the liquid. The different annexes have conical brass £ s. d. mounts and can therefore easily be interchanged. The apparatus has a lateral annex-tube so as to be able to connect it with another vessel. The piston packing is of mercury; the regulating screw fitted at the top of the apparatus should be turned in order to bring the pointer to zero. 52.488. Haldat's Apparatus, for showing that the pressure of liquids depends on their height and the surface of the bottom of the columns and not upon the capacities of the vessels, Figure, with 4 different tubes 2. 10. 0 52.489. Hartwich's Apparatus for the Hydrostatic Paradox, Figs. A, B and C (Ztschr. f. d. phys. u. chem. U. 16, 1903, p. 275), consisting of 3 single pieces of apparatus ... 4. 0. 0 If the vessels are filled with water, the vessel A is lifted up by buoyancy, vessel B sinks on account of the action of bottom pressure, while the cylindrical vessel, Fig. C, remains motionless as neither pressure at base nor buoyancy bring any action to bear on this. 52.490. Sire's Apparatus, Figure, for showing the Hydrostatic Paradox, with 2 connecting cocks and 1 discharge cock 2. 10. 0 The following can be shown by the apparatus: (1) that the pressure at the base is independent of the quantity of liquid; (2) that the pressure at base depends on the extent of surface at base and on the level of the liquid; and (3) that this pressure is equal to the weight of a column of liquid whose base is the compressed surface and whose height is the height of compression. Cl. 721, 722, 726, 5824. 342 Equilibrium of Liquids. No. 52492- 52 495. 1 : 7. 52 496. 1 : 7. 52 492. 52 494. 1 : 6. 52497. 1:18. 52499. 1:14. 52 500. 1 = 12. 0. 6.0 52,492. Buoyancy Apparatus, simple, Figure, open glass cylinder closed by plane alumi- £ s. d. nium plate 0. 4. 6 52.494. --idem, Figure, open glass cylinder with metal mount, aluminium plate and glass vessel (Fr. phys. Techn. I, 2, Fig. 2395 [I, Fig. 169]; Gan.-Man., Fig. 97; Gan.- Akt., Fig. 78) The bottom plate of the inner cylinder is drawn up by a thread, the outer cylinder being filled with water; the plate is then firmly held in place by the pressure at base. If now the inner cylinder is filled with water to the level of the outer, the plate falls down. 52.495. 3 Communicating Tubes, on one wood board, Figure 0. 8. 0 52.496. Communicating Tubes, on stand, 4 different width and differently bent tubes, Figure 0. 4.0 52.497. - - idem, with large glass vessel and stopcock, Figure 1.12.0 52.498. Communicating Vessels (M. T., Fig. 59) 0. 2. 0 52.499. Communicating Water Vessels, Figure (Kolbe-Skellon, Introduction to Electricity, Parti, Figs. 64 to 66), with graduation, two of equal and two of unequal diameter, con- necting tube with cock, also suitable for Capacity Comparisons, with centimetre graduations 1 . I . n 52.500. Channel Balance, with simple stand, Figure 1. 0. 0 52.501. -- idem, better type, dismountable, stand with ball bearings, in box, Figure i.io. 0 :•!'. 502. Model of the Channel Balance, after Friedr. C. G. Miiller (M. T., Fig. 60) .... o. 8. 0 52.503. U-shaped Tubes for liquids of different gravity, Figure, on wood stand, with graduation, simple 0. 5. 0 52.504. - - idem, 500 mm long, Figure, with white and red graduations, with polished wood stand 0. in. n 52.505. -- idem, with levelling screws (Gan.-Man., Fig. 104; Gan.-Akt., Fig. 84). ... 1. 4.0 52,507. — idem, after Friedr. C. G. Miiller, with discharge cock (M. T., Fig. 61) ... 0.10.0 < I. :.H34, 730, 739,5828, 741, 2121, 745. No. 52512. Buoyancy. Communicating Tubes. Archimedi's Principle. 52 508. 52501. 1:12. 52 509. 1:1. 52503. 1:10. 52504. 1: 10. 52505. 1 : 10. 52 512. 1 : 8. 52.508. Apparatus for proving the Archimedian Law, Figure The apparatus consists of 1 wide glass vessel and 1 glass cylinder 250 mm long, into which a 50 mm wide hollow brass cylinder fits so as to be liquid-tight. If the cylinder is sunk in a vessel containing water, the piston is raised up, and it should now be noted that the piston is hollow, but is heavier than the water which it displaces. The action of the suction pump can also be explained with the apparatus. 52.509. Solid and Hollow Cylinders for explaining the Archimedian Principle, Figure (M. P. I, Figs. 375, 376 [373, 374]) 52.510. — idem, smaller 52.511. Apparatus for explaining the Archimedian Principle, after Weinhold, Figure, in order to enable the experiment to be made with dissymmetrically shaped bodies as well (W. D., Fig. Ill [100]; Ztsohr. f. d. phys. u. chem. U. 2, 1888/1889, p. 35) . . Metal Cube with Hollow Cube: see Nos. 51,511—51,513, p. 230. 52.512. Apparatus for demonstrating the Archimedian Principle, after Sire, Figure (Carls Eepertorium 10, p. 451) The apparatus comprises: 1 flat balance with upper dish, 1 stand with 2 beakers and carrier (ad- justable) for the body to be immersed; 1 overflow vessel and 1 discharge vessel with cock. It is pos- sible to show with the apparatus: (1) that a body plunged in a liquid is submitted to an upward pressure which is equal in magnitude to the weight of the quantity of liquid displaced; (2) that the increase of pressure on the bottom of the vessel is equal to the pressure of the liquid on the immersed body; (3) that a body floats when it displaces a volume of water whose weight is just as great as that of the body itself. £ s. d. 0.14.0 0. 10. 0 0. 8.0 0. 9.0 3. 5.0 Hydrostatic Balances: see Nos. 51,573—51,602, pp. 236—240. Cl. 746, 5774, 747, 748, 5821, 749. 344 Equilibrium of Liquids. No. 52513 — 52 514. 1 : 5. 52 513. 1 : 8. 52 517. 1 : 3. 52519. 1:10. 52 520. 1 : 4. 52,513. Float Apparatus, after Schellen, Figure, for showing that a floating body becomes £ s. d. immersed in the liquid until the volume of liquid displaced by it becomes equivalent to its own weight (explanation of the hydrometer) 0. 15. 0 The apparatus consists of 1 glass cylinder with eduction tube, a 200 ccm hollow displacing float, 4 loading weights of 20 g and a measuring glass. 52,514. - - idem, simpler, Figure (W. u. E. phys. Prakt., Fig. 46) 52.515. Float and Glass Cylinder with plane base, for float experiments (W. D., Fig. 116 [105]) 52.516. --idem, in form shown in Fig. 52,516, for showing that the force compressed by the body on the bottom depends on the height of the liquid column bearing on it . 52.517. Float, Figure, after Haedicke, with Cylindrical Vessel, Glass Cylinder and Glass Plate (W. D., Fig. 117 [106]) 52,518. Apparatus for showing that a floating body displaces a certain quantity of water when loaded corresponding to the weight of the load (Fr. phys. Techn. I, 2, Fig. 2420) . . The floating body carries a collecting vessel, which is placed under the water trough, and into this vessel water can flow out of the trough. The quantity of water bearing on the floater causes the floater to sink down into the trough to such extent that the position of the water in the trough, as shown by a water gauge, ramains unchanged in spite of the loss of water which occurs when it flows out. .~>L'..~ilii. Float Apparatus, after Vogel, Figure, with arrangement for eliminating buoyancy (Fr. phys. Techn. I, Fig. 2417) 0. 10. 0 0. 6.0 0. 4.0 0. 8.0 3.10.0 1.14.0 52,r>2. o The bell is placed loosely <>n tin- bottom of the full vessel and a current of air blown through the orifice c. The bell thereupon remains fixed as though attracted by suction. Cl. 3330. 764, 5778, 73,-., .'.771, 73(i. No. 52531. Floaters. Metacentres. Displacing Cylinders. 345 52523. 1:12. 52526. 1:3. 52521. 3: 10. 52 528. 1 : 2. 52 529. 1 : 2. £ s. d. 52.521. Float, after Hartl, Figure (Ztschr. f. d. phys. u. chem. U. 9, 1896, p. 121) . 0. 18. 0 The apparatus is used for explaining the conditions for the floating of the body, and also for explaining the difference between hydraulic and hydrostatic pressure. 52.522. - - idem, different pattern (Ztschr. f. d. phys. u. chem. U. 9, 1896, p. 122; Fr. phys. Techn. I, 2, Fig. 2419) 0. 18. 0 52.523. Buoyancy and Metacentre Apparatus, as suggested by Haedicke, Figure, glass vessel with discharge cock, floating body with adjustable web and stand with holder (Fr. phys. Techn. I, 2, Fig. 2422) 3. 0. 0 52.524. Half-Cylinder for the Metacentre, of wood, as suggested by Friedr. C. G. Miiller (M. T., Fig. 70) 0. 2. 0 52.525. Section of Cylinder with 2 equilibrium positions (Fr. phys. Techn. I, 2, Fig. 2423). 0. 3.0 52.526. Cold Water Float, Hollow Brass Sphere, Figure, for demonstrating the change in specific gravity of water by heat, floating in cold water and sinking in warm, 40 mm diameter, without glass vessel 0. 4. 0 52.528. Glass Body, Figure, floating in cold water, sinking in warm water or alcohol . 0. 1. 6 52.529. Small Flask and Watch Glass, as suggested by Al Biruni, for determining the specific gravity of solids, Figure (W. u. E. phys. Prakt., Fig. 36; Fr. phys. Techn. I, 2, Fig. 2303) 0. 2. 0 51,746. Displacing Cylinder, for determining the specific gravity of solids, Fig. 51,746, p. 250, with lateral eduction pipe (W. D., Fig. 57 [52]) 0. 5. 0 52,531. Displacing Apparatus as suggested by Eebenstorff, cf. Fig. 52,533; specially suitable for rapid density determinations on pieces of mineral as large as a man's fist, also for students' use (Ztschr. f. d. phys. u. chem. U. 19, 1906, p. 149); small pattern . 1.16.0 The apparatus comprises: 1 vertical cylindrical glass with lateral tubulure, 3 stoppers with different discharge tubes, 1 float going to 350 grams, 1 calibrated receiving vessel for 600 com, graduated every 5 com, 1 linoleum disc for protecting the bottom of the cylindrical glass. Cl. 731, 780, 737, 4162, 775. 346 Equilibrium of Liquids. No. 52532 — 52 533. 1 : 10. [52534. 1:10. 52 536. 1 : 9. 52 542. 1 : 6. 52 544. 1 : 8. 52.532. Glass Bell with lead weight, for determining volume of gases, for preceding Displacing Apparatus, cf. Fig. 52,534 52.533. Displacing Apparatus, as suggested by Eebenstorff, large pattern, for pieces to 1 kg weight, with 1000 ccm measuring glass, Figure 52.534. Large Glass Bell with lead weight, for volume determinations of gases, Figure 52.535. Measuring Cylinder for 200 ccm, for accurately measuring small pieces 52.536. Burette with Communicating Vessel, after Miihlenbein, Figure, for determining the sp. gravity of solids (Ztschr. f. d. phys. u. chem. U. 7, 1893/94, p. 23; Fr. phys. Techn. I, 2, Fig. 2304), with 3 test pieces of lead, brass and iron, each 150 g weight Before starting the experiment the glass vessel is sunk until the coloured water contained in it is at zero both in the glass tube and the observation tube; the body is then immersed and the liquid surface is prevented from rising, by raising the glass vessel, until the meniscus is again on the mark in the observation tube. The water displaced is now in the burette and the volume of the body can be read direct in ccm. It is now only necessary to divide the absolute weight of the test body, in grams, by the volume in ccm, in order to get the sp. gravity. Overflow Vessels: see Nos. 51,746 — 51,748, p. 250. Displacing Bodies. List No. 52,537 Adjusted at 15° C. Displaces 5 g £ 0. 4. 0 52.542. Hydrometer, after Nicholson, Figure, of brass, with wide tube for obtaining con- siderable buoyancy, and with arrangement for determining the specific gravity of solids lighter than water; also suitable for determining the sp. gravity of liquids (M. P. I, Fig. 392 [383]; Fr. phys. Techn. I, 2, Fig. 2408) 52.543. — idem, of glass 52.544. - - idem, after Tralles (W. D., Fig. 118 [107]), Figure 52.545. - - idem, after Fahrenheit, Hydrometer for liquids (Gan.-Akt.-Eein., Fjg. 102), with glass cylinder 52.546. 2 Hydrometers, after Baume, for light and heavy liquids respectively 52,538 17.5° C. 52,539 27.5° C. 52,540 100° C. 52,541 60° Fahr. 0.4.0 5g 0.4.0 0.°4. 6 100 grains 0.4.6 £ «. d. 0. 5.0 2. 8.0 0. 6.0 0. 2.0 •2. 0.0 52.547. 2 Hydrometers for heavy and light liquids, simple pattern, with glass cylinder, Figure, the scale of the first is from 0.7 — 1.0 and of the second 1.0 to 2.0 52.548. Hydrometer of high Sensitivity, Figure, with marks for density 1.000, 1.001 and 1.002, for demonstrating the different densities of pure water and of salt solutions, with unscrewable mercury bulb 0.16.0 0. :>. o 1. o.o 0. 5. 0 0. 3. 0 0. 4.0 0.15.0 (I. :il>44, 3644, 782, 702, 5773. No. 52557. Specific Gravity. Hydrometers. 347 52 554. 1 : 5. 52 555. 1 : 9. 52 548. 1 : 5. 52 553. 1 : 5. 52 547. 1 : 5. 52 552. 1 : 5. 52 556. 1 : 6. 52.549. Hydrometer, high Sensitivity Pattern, for specific gravities of 0.997, 0.998, 0.999 and £ a. d. 1.000, for measuring the density of water between 0° and 25° C. and for showing the Density Maximum 0. 15. 0 52.550. Universal Hydrometer, from 0.700 to 2.000, with thermometer 0. 4. 6 52.551. - - idem, without thermometer 0. 3. 6 52.552. Hydrometer, for very accurately determining the sp. gravity from 0.700 to 2.000, comprising 4 spindles with thermometer in elegant case, and 1 measuring jar, Figure 0.18.0 52.553. Large, Flat Hydrometer for measuring the Density of Acids, Figure, with large, plain black and red scale from 1.180 to 1.240 0. 3. 0 The Hydrometer is quite flat in shape, thus enabling it to be immersed between the accumu- lator plates of stationary batteries. The scale indicates thousandths. Not suitable for portable accumulators. 52.554. Specific Gravity Indicator, Figure, Hydrometer with glass vessel, rubber ball and tubing, for conveniently determining the sp. gr. of the acid in portable accumulators 0. 7. 0 If acid is sucked up by the rubber ball into the glass vessel the density of the acid can be easily read off on a hydrometer contained in the vessel. 52.555. 27 Indicators, of glass, differently loaded, Figure, each Indicator plunges into a liquid when the sp. gr. of the latter is equal to that marked on the indicator (Fr. phys. Techn. I, 2, Fig. 2471) 1. 0. 0 The Indicators correspond to the sp. gravity of 0.7 to 2.0 in stages of 0.05. 52.556. Sike's Hydrometer, Figure, heavily gilt, with thermometer, instructions, tables and comparison rule, in elegant mahogany box and with test glass 4. 10. 0 52.557. Alcoholimeter, after Tralles, for 30—100%, graduated in l/2% 0. 2. 0 Cl. 766, 767, 2276, 68, 779 l, 768, 3645. 348 Equilibrium of Liquids. \... .V2558 — 52 558. 1 : 8. 52 560 B. 1:6. 52562. 1:6. 52 560 A. 1:4. 52 566. 1 : 4. 52.558. Differential Hydro-Pycnometer, after Eebenstorff, Figure, without glass cylinder (Ztschr. f. d. phys. u. chem. U. 17, 1904, p. 339) The instrument is used for accurately determining the sp. gr. from 0.5 — 2.0, requires only a very small quantity of liquid and can be used in the preparatory and laboratory work of the teacher as a precision hydrometer. It gives an opportunity for exercises on the Archimedian Principle as well as for discussing the advantages and disadvantages of the various methods for determining density in the preparatory practical instruction. 52.559. Glass Cylinder for Differential Hydro-Pycnometer No. 52,558, 445 mm high, 90 mm wide, all for Hydrometer No. 52,560 52.560. Hydrometer with Centigram Spindle, after Eebenstorff (Ztschr. f. d. phys. u. chem. U. 19, 1906, p. 10), Figs. A and B, of glass, in elegant case, with 5 weights each for water and air in separate wood box. Price without glass cylinder (see No. 52,559) The Centigram Spindle is arranged so as to screw off and is provided with coloured scale. This Hydrometer is specially adapted for instruction in chemistry and mineralogy, it permits of rapid working. 52.561. Pneumatic Densimeter, for determining the Specific Gravity of Liquids, after Boyle, 2 tubes with 1 pump, on graduated stand 52.562. - - idem, after Mohr (Alexander Hydrometer), Figure, instead of being fitted with pump, with rubber ball and valve (M. P. I, Fig. 399) 52.563. - - idem, after Babinet, without bellows (M. P. I, Fig. 364), with 2 U-shaped tul><-s and graduation for accurately reading differences of height £ s. d. 1. 8. 0 0. 3. 6 1. 4. 0 1. 8. 0 i. :.. ii 1. 0. 0 CI. 3332, 3329, 781, -. 770. Xo. 52 576. Pycnometers. Hydrometers. Densimeters. Comparison Bodies. 349 52567. 1:4. 52568. 52569. 1:4. 1:4. 52571. 1:7. 52570. 1 :2. 52574. 2:5. 52 572. 1 : 2. 52,564. 2 Immersion Tubes, after Friedr. C. G. Miiller, for light and heavy liquids respectively ! (M. P., Fig. 63) . . . ' U-shaped Tubes: see p. 343. 51,749. Pycnometer, F i g. 51,749, p. 250, for determining the sp. gravity of solids and liquids; comprising small flask with cover plate ground on, spherical pipette and tripod (W. D., Figs. 58 and 59 [53 and 54]), without glass jar 52.566. - - idem, with thermometer ground in and graduated tube, Figure, for deter- mining the sp. gravity of liquids (W. and' E. phys. Prakt., Fig. 38) 52.567. Small Flask, for determining the specif ic gravity of solid bodies soluble in water, but insoluble in alcohol, Figure 52.568. - - i d e m, for substances insoluble in water, as suggested by Eegnault, Figure (Gan.-Man., Fig. 116) £ s. d. 0. 8. 0 52.569. - - idem, simple, after Gay-Lussac, for liquids, Figure 52.570. -- idem, straight pattern, after Eegnault, Figure (Gan.-Man., Fig. 117) . . 52.571. Pycnometer, after Sprengel, for determining the specific gravity of liquids, Figure (W. u. E. phys. Prakt., Figs. 39 and 40) 52.572. --idem, Figure, with Thermometer fused in and Glass Cap ground on for accurate measurements (M. P. I, Fig. 391), with filling tube 0. 3. 0 0. 5. 0 0. 1. 6 0. 1. 6 0. 1. 0 0. 1. 0 0. 3. 0 52,573. 1 Cubic Centimetre, of brass, copper, lead or aluminium. Price, each 52.574. 12 Cubic Centimetres in case, Figure, of magnesium, antimony, tin, German silver, copper, silver, aluminium, zinc, iron, brass, bismuth, lead (Fr. phys. Techn. I, 2, Fig. 2240) 52.575. 12 Bars, all of same weight (10 g) and same section, in case (Fr. phys. Techn. I, 2, Fig. 2241) 52.576. 4 Metal Strips, of aluminium, zinc, copper, lead, in case, of equal width, equal thickness and equal weight, the lengths corresponding inversely to the different specific gravity 0. 9. 6 0. 3. 0 1. 4. 0 1. 6. 0 0. 8. 0 Cl. 771,772, 773, 777, 5552, 774, 48BO. 350 Equilibrium and Motion of Liquids. No. 52 577 - PG BSKNMNSEZZ/VM J.S so V .11588 K i) Si n IS n 70 It II Metallbleche La'ngen 'iimimgekehrtenVerhaltnisse ftf specif techenGeiyichte NachArendt,l_ehrbuchder anorjanischen Chemie. 52577. 1:13. 52 578. 1 : 5. 52580. 1:7. 52 579. 1 : 5- 52 581. 1 = 15. 52582. 1:12. 52583. 1:13. 52.577. 14 Metal Strips, after Arendt, Figure, of platinum, gold, lead, silver, copper, German silver, brass, nickel, steel, iron, tin, zinc, aluminium and magnesium, of same thickness, width and weight; lengths inversely proportional to specific gravity . . . The construction is very accurate and all metals are genuine. 52.578. 3 Cylindrical Bodies of the same weight, after Kolbe, Figure, of aluminium, iron and lead 52.579. Cylindrical Glass Vessel with 4 Liquids of different specific gravity, Figure . . 52.580. 6 Liquids of different specific gravities, Figure (Mercury, Sulphuric Acid, Glycerine, Water, Petroleum, Sulphuric Ether), in glass tubes of same length and width, in wood frame. The lengths of the liquid columns are in inverse ratio to the specific gravities Motion of Liquids. 52.581. Outflow Apparatus, for experiments on flow out of an orifice in a thin wall, Figure (W. D., Figs. 119, 120 [108, 109]), consisting of Mariotte flask, rubber tubing, glass tube, outflow vessel, 1 mouthpiece and small table 52.582. --idem, for experiments on outflow velocities at different pressures, Figure A sheet iron cylinder, 75 cm high, with a wide vessel at the top for more easily maintaining a constant level, and with 3 orifices at distances of ratio 1:4:9 provided below the level, for showing that the quantities flowing out are proportional to the square roots of the heights of pressure (Torri- celli's Theorem). 52.583. - - idem, after Weisbach, with vessel 1 m high, Figure, with stuffing boxes (M. P. I, Fig. 402 [392]), on plate with levelling screws £ s. d. 1. 16. 0 0. 18. 0 0. 5. 0 0.16.0 1.15.0 1. 0.0 2.12.0 CI. 779,5079,3334.5775. 783, 784, 785. No. 52 588. Comparison Bodies and Liquids. Outflowing Water Jet. 351 52 586. 1 : 15. 52.584. Outflow Apparatus, for proving Torricelli's Law on velocity and quantity of outflow at different hydrostatic pressures, Figure, with 5 sliding plugs, constant level overflow pipe, catching trough and table Each outflow support has a manometer and 3 different tubes are provided for each slider for showing the increase in the quantities enanating through annex pipes; the catching trough is gra- duated and has a sliding diaphragm. The whole rests on a wood table covered with sheet iron. 52.585. - - idem, simpler, annex tubes without manometers 52.586. Haiti's Apparatus for experiments on velocity and quantity of outflow at different pressures, for showing the diminution of pressure, the reacting pressure of liquids, and for demonstrating the projection parabola, Figure (Fr. phys. Techn., Figs. 3530, 3538) 52.587. Well Spring, of glass, comprising glass vessel with glass tube and point (Meyer, Natur- lehre, Fig. 154; Gan.-Man., Fig. 127) * 52,588. Apparatus for showing that a Jet of Water flowing into the air is composed of drops, Figure Suitable for setting up on the projection lantern. A stroboscopic disc is placed in front of the water vessel with outflow aperture; with the aid of this disc it is possible to render visible (when the disc is rapidly rotated) the composition of the water jet of drops. £ s. d. 11. 0.0 9. 0.0 7. 0.0 0. 2.0 1. 6.0 # Can be used with the projection apparatus. Cl. 3335, 3283, 3336. 352 Equilibrium of Liquids. No. 52 589 - 52590. 1:15. 52 592. 1 : 7. 52591. 1:10. 52 593. 1 : 10. 52 595. 1 : 10. # 52,589. Apparatus for showing the parabolic form of the outflowing Water Jet; can be , £ *• ''• used at same time for demonstrating total reflection in a water jet (W. D., Fig. 291 [274]) j 0. 16. 0 * 52,590. — idem, with vessel 1 m high, Figure, on support, with 4 coloured discs for inserting 52,591. Reaction Float, Figure, for showing the back impact of outflowing liquids, with water vessel (Weber, Lehrb. d. Phys., 10th edn., 1897, Fig. 60) 2. 0.0 0. 15. 0 52,592. Reaction Apparatus, Figure, for showing hydrodynamic lateral pressure. . . . •VJ.593. - - idem, after Hartl, Figure, for showing the back impact of outflowing liquids, gases and vapours (Ztschr. f. d. phys. u. chem. U. 10, 1897, p. 234) The apparatus consists of a stand carrying a metal tube hanging from a rubber tube, the metal tube having two opposite apertures, a gram scale and a trough. The two apertures are in size as 1 : 2 and can be alternately closed. At the, upper end of the rubber tubing either a funnel (for C\|M n- meiits with liquids), a mouthpiece (for experiments with gases), or a sheet irqn sphere (for experiments with vapours) can be arranged, these three latter being given in with the apparatus. 0.14.0 1. 4.0 ('an be used \\ith the projection apparatus. ft. 342, 5091, 3337. 790. 789. No. .V->603. Outflowing Water Jet and its Reaction-Pressure. 353 52596. 1:13. 52 597. 1 : 8. 52598. 1:10. 52 600. 1 : 10. 52 602. 1 : 4. 52 603. 1 : 10. 52,594. Lateral Pressure Apparatus, after Kleiber, for demonstrating hydrodynamic lateral £ s- d. pressure (Kleiber, Lehrb. d. Phys. f. Gymnas., Fig. 85), consisting of a small water balance with aperture at the end j 0. 15. o .vj.r>95. Apparatus (Haiti's), Figure, for experimental measurements on Velocities of Outflow, Quantity of Outflow and Reaction-Pressure (Ztschr. f. d. phys. u. chem. U. 9, 1896, p. 234) 4. 4. 0 The outflow orifice can be placed either in the bottom or the side wall. Five different plates permit of varying the form and size of the same, while the pressure is varied by small inset tubes 25 and 50 cm long. A sheet iron rule, on which the water jet gives its velocity direct, is used for deter- mining the velocity of outflow. The reaction-pressure is given automatically on the pressure scale which is divided in grams. The apparatus works with thorough accuracy without large quantities of water being necessary. 52,596. Barker's Mill (Reaction Wheel), with water tank, Figure .">L'..")97. -- idem, entirely of metal, Figure; can also be used as a well-spring . . . 1. 1. 0. 0 0. 0 52,598. Barker's Mill, Figure, of metal, with rotating vessel 0. 16. 0 12. 0 5. 0 8. 0 .~iL'.r>99. - - idem, smaller, with glass water vessel 52,600. --idem, Figure, of glass and metal, with polished wood stand 52,602. Hydraulic Ram, after Montgolfier, of glass, Figure (W. D., Fig. 126 [114 B]) .0. 0. -idem, of metal and glass, Figure (W. D., Fig. 125 [114 A]), with pipe line 4 m long; can be easily taken apart; excellent in action; with sheet iron vessel for placing underneath for the water running out of the impact valve 3. 12. 0 Kl. 792,793, 791, 794,797,798. 354 Motion of Liquids. No. 52 604 - 52 604. 52611. 1 : 1. 52 616. 1 = 6. 52615. 1:13. 52,604. Hydraulic Ram, Figure, with water tank and vessel for setting underneath, on * one stand 3. 51,601. Plate and Hollow Hemisphere for measuring the Impact Pressure of Liquids (M. T.. pp. 108 and 109) 0. 52.606. Water-Lead Mouthpiece, for experiments on Impact and Reaction-pressure (M. T., Figs. 74 and 75) 0. 52.607. Indifferent Immersion Body, for impact pressure experiments (M. T., Fig. 76) . . 0. 52.608. Model of a Dressing Machine (M. T., Fig. 77) (). 52.609. Glass Vessel for Whirlpool (Hofler, Physik, Fig. 177) 0. 52.610. Diminution of Pressure Apparatus, after Friedr. C. G. Miiller (M. T., Fig. 73) . . 0. 52.611. Apparatus for showing Diminution of Pressure in Cylindrical Tubes, Figure (W. i D., Fig. 121 [110]) 1. 52.612. Attachment for above, for outflow experiments on an orifice in a thin wall (W. D., Fig. 120 [100]) (». 52.613. Two Glass Tubes, for showing pressure-change in bent or constricted tubes (W. 1)., Figs. 122 and !•_':> [Ill and 112]), for attaching to Apparatus No. 52,611 or directly to the water-lead 0. .">:.'. til 4. Glass Tube, for showing the sucking action of flowing water (W. D., Fig. 124 [113]) 0. 52,615. Pitot Tube, modified by Darcy and Reichenbach, Figure, for measuring velocity of flow .6. This apparatus is independent of a time observation. It has two upright tubes alongside each other, which are horizontally bent underneath. One is for taking up the impart of flowing water, while the other >hows the hydrostatic pressure of the surface of the water. Both tubes have a suction tube connected to them at their upper ends: this suction tuhe can be closed by a cock. By this arrangement it is possible to raise or lower the \\ater < olumns, as re- quired, for convenience in reading, for carrying out the comparison in height. The lower cock which cuts off the water columns from the lu)n> can lie closed and opened by ' two cords. ,-. d. 15. 0 3. 0 2. 0 2. 0 3. 0 •2. 38 b. - - i d e in, larger still, output 1/8rd HP at 4 atm. water-pressure .">LM>39. Model of the Ship's Screw, Figure, and of the Airship Propeller The screw is fitted on a small carriage and can be rapidly rotated by pulling a cord, and the carriage moved backwards or forwards. t 52,640. Model of a Wheel with movable Paddles, for steamers ,15. 0.0 5. 0.0 7. 5.0 9.10.0 1. 4.0 13. 0.0 52,641. Model of an Archimedian Water Screw, Figure (Fr. phys. Techn. I, 2, Fig. 2313 [I, Fig. 553]) 1 . 0. 0 52.K12. Model of a Discharging Water-drawing Wheel 30. 0.0 The items marked t are carefully constructed models for Universities and Colleges. cl- 3647, «io, 5161, 812,811. 358 Motion and Molecular Effects of Liquids. N... :.. 52 643. 1 : 6. 52 644. 1 : 5. 52 645. 1 : 5. t 52,643. Model of a medium-high Discharging Water-drawing Wheel, Figure 52,644. Model of an Apparatus for raising the Sluices, with rack and pinion, Figure. . 52.645. - - i d e in, with Screw and Spur Wheels, Figure 52.646. — i d e m, with Switch-gear and with Chain-pull . Molecular Effects of Liquids. f s. .1. 15. d. (> 5. (>. (» ti. in. d 7.10. it 52.647. Piezometer, after Weiuhold, Figure (W. D., Fig. 127 [115]), suitable for the Pro- jection Lantern, for showing the small degree of compressibility of liquids _. .">. n 52.648. -- idem, after Grimsehl (Grimsehl, Lehrb. d. J'liys., 1909, Fig. 214; /tschr. f. d. phys. u. chem. U. 20, 1907, p. 7). The compression vessel with the liquids in be tested is kept at the same pressure inside and outside by mercury. Price without mercury 1. is. d 52.649. Piezometer, after Oersted, Figure, with Pressure Screw, with m:i>>i\e uhiss cylinder for 10 atm., with insets (pressure vessel, thermometer, air manometer) 4.1(1.0 The items marked f are carefully constructed models for I'niversities anil Cl. 3646,3(11- No. -.2657. Water Drawing Wheels, Sluica raising Apparatus. Piezometers and Accessories. 359 52 647. 1 : 5. 52649. 1:8. 52 650. 1 : 8. 52 657. 1 : 8. 52 654. 1 : 5. 52 656. 1 : 5. 2,650. Piezometer, after Oersted, Figure, with pressure pump and spring pressure gauge, £ s- d. tested to 10 atm.; easy and convenient to manipulate and fill; with discharge cock, 1 pressure vessel, graduated, and mercury vessel (Fr. phys. Techn. I, 2, Fig. 2524) . i 8. 0. 0 2.651. - - idem, with Safety Valve 2.652. Attachment with Pressure Vessel, Thermometer and Air Manometer for Piezometers Nos. 52,650 and 52,651, cf. Fig. 52,649 2.653. Attachment with two Gas Pressure Tubes, after Despretz, for comparing the differing compressibility of gases (Chwolson, Lehrb. I, Pig. 227) 2.654. Attachment with 1 Ether Vessel and 1 Water Vessel, for the Oersted Piezometer, Figure, for comparative experiments i,655. Attachment, consisting of Lead Plate and Ether Thermometer in protecting tube, and Manometer, for demonstrating the lowering of the melting point of water by pressure, after Thomson (M. P., HI, Fig. 327 [II, 2, Fig. 95]), for the Oersted Piezometer '. :,656. Attachment with Four Tubes, after Magnus, Figure, for liquifying gases by pressure (M. P., HI. Fig. 306 [II, 2, Fig. 163]) Four short barometer tubes are contained in one common vessel and can be fed with mercury and with different gases which are present above them. 2,657. Piezometer, after Eegnault, Figure (M. P., HI, Fig. 152 [I, Fig. 412]), with glass vessel and nickelled metal parts 8. 10. 0 i. o. o 1. 0. 0 i. 10. 2. 5. II 1. 10. 0 6. 10. 0 Cl. 5768, 819, 5404, 822. 821, 3341. 360 Molecular Effects of Liquids. N.I. :.•_• i ;.-,;i 52 659. 1 : 5. 52 660. 1 : 6. 52 663. 1 : 3. 52,659. Plateau's Apparatus, for showing the flattening of a Sphere of Oil rotating in an alco- holic solution, with rectangular glass box, Figure (Fr. phys. Techn. I, 2, Fig. 3522) * 52,660. --idem (Weinhold's) (W. D., Fig. 85 [78]), Figure, for use with the Projection Apparatus by employing one of the apparatus for projecting horizontal objects, Nos. 51,032 to 51,039 .~>2,661. 4 Cohesion Plates, Figure, for suspending on the balance, 40 mm diameter, of ground glass, polished ebonite, brass and iron (W. D., p. 167 [144]), for showing the cohesion of wetting liquids and the adhesion of non-wetting liquids on solids .... .">i'.(»62. 4 Hollow Spheres, of glass, 2 of these coated with paraffin, for demonstrating capillary attraction and repulsion (M. P., Ill, Figs. 191 — 193 [I, Figs. 448 — 450]) .M'. i»i»3. Plateau's Equal-weight Figures, for soap solution, set of 4, F i g u r e, circle with feet, circle with handle, triangle and cube (cf. Fr. phys. Techn. I, 2, Figs. 2446 — 2450) :>:_', uiil. Vacuum Syphon, after Weinhold - Stcinbrinek, Figure. Cohesion Syphon filled with water, approx. 1 in long (Jahrliiicher 1'iir \\issenschaftl. Hotanik. Vol. ll', part 4, pp. 585 et seq.), working by the cohesion of the liquid particles s. (> 1. o. (> o. 6. o u. I. (i # Can be used with Projection Apparatus. (1. sic, 5863, S'.'j. (>. 83, If., u N... .VJB73. Piezometers. Cohesion. Adhesion. Surface Tension. 361 52664. 1: 12. 52 666. 1 : 10. 52 672. 1 : 4. 52 668. 1 : 3. 52 673. 1 : 8. 52,665. Vacuum Syphon as No. 52,664, with. Mercury and Water Filling 52,066. -- idem, simple, after Weinhold, Figure (W. D., Fig. 171; Ztschr. f. d. phys. u. chem. U. 17, 1904, p. 152) 52,667. Cohesion and Adhesion Tube, after Leduc and Sacerdote (Gan.-Man., Figs. 26 and27)> for showing the cohesion and adhesion of liquids, for connecting up to the Vacuum Pump • 52,668. Apparatus for showing that Liquids endeavour to Contract, Figure, but with glass cock (W. D., Fig. 130 [118]) 2,670. - - idem, simple (W. D., Fig. 128 [116]) * 52, 671. Apparatus for demonstrating Surface Tension (W. D., Fig. 131 [119]), U-shaped glass tube with unequal limbs, with stand 52.672. Apparatus for showing and measuring Surface Tension, Figure (W. u. E. phys. Prakt., Fig. 74) The measurement is carried out by observing the degree of ascension in capillary tubes which are fastened on a glass scale by means of a rubber ring. The cubical trough containing the liquid consists of plate glass sheets of 5 cm side. 52.673. Apparatus after Eebenstorff, for measuring Surface Tension, capillary ascension, Figure (Ztschr. f. d. phys. u. chem. U. 19, 1906, p. 26, Fig. 2) . .' The apparatus consists of a manometer for coloured water, a number of capillary tubes together with stand and glasses, and a pressure tube extending in width downwards, with beaker and 2 hose pieces each of 15 cm length. £ s. d. 1. 1.0 0. 6. 0 I ! 0. 12. 0 0. 6. 0 0. 1. 0 0. 4. 0 3. 0. 0 # Can be used with the Projection Apparatus. Cl. 4023, 3752, 820, 4976. 1. 0. 0 827, 362 Molecular Effects of Liquids. No. 52 674. 1 : 10. 52 676 A. 1 : 4. 52 676B. 1 : 1. 52 679. 1 : 5. 52 680. 1 : 5. 52 682. 1 : 2. 52,674. Apparatus after Eebenstorff, for reducing the Surface Tension of Water by Ether, £ Figure (Ztschr. f. d. phys. u. chem. U. 19, 1906, p. 27, Fig. 3) 0. The apparatus consists of a glass bell with nozzle seal, a glass dish, a stand for holding the bell, a weighted compression bell in a glass cylinder, a pipette for ether and a 30 cm length of rubber tubing. S. (1. 13. 0 * 52,675. Dropping Apparatus, after Friedr. C. G. Muller, for showing Surface Tension (M. T., Fig. 78), suitable for the Projection Lantern The liquid used for dropping is coloured colza oil in a mixture of water and alcohol, of such density that the drops fall slowly. 52,676. Dropping Pipette, for determining the Constant of Capillarity, Figures A and B (W. u. E. phys. Prakt., Figs. 78 and 79) Fig. B shows the lower smoothly polished end of the pipette with drop of liquid hanging on the end. * 52,677. Wide Tube and Capillary Tube, for capillary depression of non-wetting liquids (W. D., Fig. 132 [120]) * 52,678. -- idem, with short Capillary Limb, for demonstrating Surface Tension (M. T., Fig. 79) * 52,679. 2 Wide Tubes with Capillary Tubes, for projection, F i g u r e, on stand, for demon- strating Capillary Ascension of wetting and the Capillary Depression of non-wetting liquids, e. g. coloured water and mercury * 52, 680. Wide Tube with 5 Communicating Capillary Tubes, Fign re, for the objective de- monstration of the capillary ascension of wetting liquids or the capillary depression of non-wetting liquids 0. 6. 0 0. 2. (> 0. I. 0. 3. 0 0. S. d 0. (i. u # Can be used with the Projection Apparatus. (1. 4984, 82S, 3650, 3790, 829, 830. No. 52691. Surface Tension, Capillarity. 363 Millimeter. 52 684. 1 : 4. 52 685. 1 : 2. 52 686. 1 : 2. 52 691. 1 : 4. 52.681. Apparatus for Capillary Depression and Ascension of Liquids, with 3 capillaries of £ » d. different widths, on graduated wood stand (Fr. phys. Techn. I, 2, Fig. 2451) .... 0. 8. 0 52.682. - - idem, with 4 capillaries of different widths, on graduated wood stand, Figure 0. 12. 0 52.683. Stand with 10 Communicating Capillary Tubes, Figure, graduated * 52,684. 5 different Capillary Tubes, with holder and glass vessel, Figure (Fr. phys. Techn. I, 2, Fig. 2452) 52,685. - - idem, with plane parallel glass vessel, Figure 52.686. 5 Capillary Tubes of different widths, with stand, Figure (W. D., Fig. 133 A [121 A]) 52.687. Capillary Tubes alone (Gan.-Man., Figs. 208—211) 52,688. 5 Capillary Tubes of different shapes, for showing that the capillary ascension at the same temperature is independent of the shape of the tube (Gan.-Man., Fig. 218) . . * 52,689. Apparatus for showing the behaviour of wetting and non-wetting liquids in a conical tube, Figure (W. D., Fig. 134 [122]), on stand *•> 52.690. 1 Set Capillary Tubes for demonstrating capillary ascension and depression, the pro- pagation of a drop in a conical tube, the independence of the capillary effect on the form of tube, and the migration of a drop of mercury by inequality of the surface tension produced electrolytically 52.691. Apparatus for demonstrating Migration of a Mercury Drop by the electrolytically- produced inequality of surface tension, Figure, suitable for objective observation . 0. 12. 0 0. 2. 0 0. 12. 0 0. 8. 0 0. 1. 0 0. 3. 0 0. 2. 0 0. 4. 0 8. 0 # Can be used with the Projection Apparatus. Cl. 3342, 329,5790, 5846, 330, 3533. 364 Molecular Effects of Liquids. Equilibrium of Gases. N... .'.I' IlilL' - 52692. 1:1. 52 693. 2 : 5. 52 694. 1 : 2. 52 695. 1 : 10. 52 697. 1 : 7. 52 698. 3 : 10. 52 699. 1 : 8. * 52,692. Capillary Plates, maintained in correct position by a brass wedge and spring, Figure £ - • cl- (W. D., Fig. 133 B [121 B]), without stand 0. 3. 0 * 52,693. - - idem, with stand, Figure I 0. 10. 0 * 52,694. - - idem, larger, with adjustable angle and with stand, Figure 0. 10. 0 52,695. Apparatus after Arrhenius, for determining the internal friction of Liquids, F i g u r e (W. u. E. phys. Prakt,, Fig. 67) 3. 0. 0 In a brass box, let in at the front and back with windows, is a capillary tube with ball and two marks. The specific coefficient of friction is determined by observing the times of outflow of definite quantities of liquid. With regard to Viscosimfters and Apparatus for testing Oils and Pats for their lubricating quality, kindly ask for quotations. 52,696. Apparatus after Jamin, for demonstrating the absorption of liqtiids through porous bodies (Chwolson, Lehrb. d. Phys., I, Fig. 328) A cube of chalk contains a cavity for taking a manometer, the cube being immersed in water. .)•_', 097. Striation Apparatus, after Heumann, Figure, for demonstrating the dissolving tension of salts (Fr. phys. Techn. I, 2, Fig. 2466) <)..!.(> o. Hi. () 52,697 a. Tube with supersaturated Sodium Sulphate Solution: the solution crystallises when tube i> opened (Chwolson, Physik, Vol. I, p. 620) 0. 1.0 52. !>()«. Apparatus after Uppenborn, for the Diffusion of Liquids, Figure (W. I)., Fig. 135 [123]) 0. 1. 0 52,09!). Endosmometer, after Dutrochet, Figure, with irnulnation on wood (M. P., HI, Fig. 223 [I, Fig. 465]) 0. 5. 0 ."•'_'.700. -- idem, Figure, with horixontal ascension tube (\V. I)., Fig. 136 [124]) . # Can be used with tlir Projection Apparatus. I). 1(1. 0 Cl. 33:>, 333,334, 837, 5360, 838, 839. No. r,2 706. Capillarity. Endosmose of Liquids. Universal Apparatus for the Study of Gases. 365 52700. 1:6. 52 701. 1 : (5. 52 705. 1 : 30. 52706. 1:19. 52,701. Endosmometer, after Niemoller, with vertical membranes, Figure 52.702. Endosmometer, after Pfeffer, with manometer (Liipke-Bose, Grundziige der Elektro- chemie, 5th edn., Fig. 27) 52.703. Osmose Apparatus, after Friedr. C. G. Miiller (M. T., Fig. 81) , . 52,704. Vessel for Dialysis, after Weinhold (W. D., p. 175 [153]) Two ebonite rings of 80 mm diameter fitting in each other with a sheet of parchment stretched between for receiving the white of an egg. £ s. d. 2. 0. 0 0. 8. 0 0. 10. 0 0. 5. 0. Equilibrium, Motion and Molecular Effects of Gases. Equilibrium of Gases. 52.705. Apparatus after Schaffers, for Experiments with Gases and Vapours, Figure, £ s • «'• suitable for proving Boyle's (Mariotte's) Law for Pressures which are greater or smaller than 1 atm. and for experiments on the Tensive Force of saturated and non-saturated vapours in vacuo and in air (Ztschr. f. d. phys. u. chem. U. 18, 1905, p. 217) ... 6. 0. 0 The apparatus is a combination of the Feilitzsch -Weinhold Apparatus for proving Mariotte's Law with the 3-tube apparatus as used for the laws relative to the tensive force of gases and vapours. 52.706. Apparatus for Demonstrating the Properties of Gases, after Lermantoff, Figure, for demonstrating the Barometer, Mariotte's Law, the (Icissler Mercury Air Pump, the Expansion of Air with constant volume and constant pressure respectively (Air Thermo- meter), the Yolumnometer, the Tension of saturated and non-saturated vapours . . 5. 0. 0 For observing according to 0. Lehmann's method the growth of solid and liquid crystals which are apparently alive, kindly refer to the Projection Microscopes and Accessories Nos. 51,057—51,061, pp. 183 and 184. CM. 840. 4180. .->;V.!S, 5S41. 366 EQuilibrium of Gases. No. 52707 — 52707. 1:12. 52709. 1:10. 52 710. 1 : 7. 52.707. Apparatus for Experiments with Gases, after Schneider, Figure, suitable for a large number of experiments on the theory of the equilibrium of gases and on the theory of heat; can also be used as a Gas Measuring Apparatus; suitable for school use . . The apparatus consists of 2 separate stands provided with weights, with 3 burette tubes each having two stopcocks and graduation; 1 rule with 2-coloured centimetre graduation on one side and millimetre graduation on the other; 1 round flask with rubber stopper and angle tube. The apparatus is intended for demonstration work in teaching and for students' exercises. It is suitable for the following demonstration experiments, among others: Demonstrating the Syphon Barometer (also with variable vacuum); the Testing of Barometers; the Mercury Air Pump; for pro- ducing a Vacuum Tube with the Torricellian vacuum; demonstrating boiling and re-boiling on cooling in vacuo; demonstrating the MacLeod Vacuum Gauge; for experiments on the Vapour Pressure of Ether in vacuo and in air; for the suction, conduction and measurement of quantities of gas; de- monstrating the Pressure Gauge; Gay-Lussac's Law on the Expansion of Gases at constant pressure; on the increase of Pressure of Gases when heating in constant volumes; on the variation in Volume of Gases with variation of pressure and temperature; Solubility of Gases in liquids ; measuring the Vapour Pressure of water, etc. etc. 52.708. - - idem, with iron stand 52.709. Pressure Flask, after Schneider, Figure, for measuring the Pressure in Water Leads, the Air Pressure produced by the water lead; for demonstrating Heron's Ball and the Air Chamber 52.710. Diving Bell, Figure, of glass, with light-holder, suspended in stand, for showing that air occupies a space 52.711. -- idem, with rubber bellows 52.712. Indiarubber Balloon in wood box, Figure, with loosely fitting lid and 6 iron weight- ing plates, for showing the elasticity of air If the lid, and consequently the balloon, is weighted with the iron plates, this depresses the balloon more or less. .")!'. 7 1:{. Apparatus for showing the Elasticity of Air, Figs. A and B A piston fitted with a handle and hook, moves in vacuo in a metal tube, Fig. A, provided witli a bottom piece and a hook; the tube communicates with the outer atmosphere by a stopcock. If tin- cock is closed and the piston pushed in, the piston tends to spring back when an attempt is made to pull it out. A tripod and ;i loading plate are supplied with the apparatus; the tripod being dctaelialile (Fig. B), in order to show also the Compressibility and Elasticity of the compressed air. Double Sphere for showing the Expansion of Gases: see Nos. 51,751 and 51,752, p. 250. Glass Sphere for weighing Air: see Auxiliary Apparatus for tin- Air Pump. £ s. d. 3. 12. 0 4. 10. 0 0. 18. 0 1. r>. o 1. 1'2. 0 0. 0. 0 1. 0. 0 Cl. 5433,5422, 841. -No. 52719. Universal Apparatus. Displacement in Space. Specific Gravity. 367 52712. 1:4. 52 713 B. 1:7. 52 717. 1 : 5. 52 713 A. 1:5. 52 718, 52 719 — 52 721. 1:10. 52,715. Glass Tube, for determining the Specific Gravity of Gases, after Friedr. C. G. Miiller £ s. d. (M. T., Fig. 83), for use in conjunction with pressure level No. 52,731 0. 6. 0 .")!', 716. - - idem, for the Grimsehl Gas Balance, with 3-way cock (Ztschr. f. d. phys. u. chem. TJ. 18, 1905, p. 200), for use with the Spirit Level Pressure Gauge No. 52,732 0. 3. 0 52.717. Baroscope after Schoentjes, Figure, for showing the Buoyancy of Air, with counter- poise (Fr. phys. Techn. I, 2, Figs. 2708 and 2708 a; Ztschr. f. d. phys. u. chem. U. 14, 1901, p. 166) 1. 5. 0 By increasing the hermetically closed hollow body it is shown that this appears lighter when it displaces more air. If air is allowed to force its way inside, the body then appears heavier. 52.718. Apparatus for Experimental Measurements with Air Balloons, Figure, after Eeben- storff (Ztschr. f. d. phys. u. chem. U. 19, 1906, p. 98), complete, without clamping stand 2. 0. 0 For experimental measurements on the buoyancy of balloons filled with hydrogen or house gas. The apparatus consists of 2 tubulated glass flasks with rubber connecting tubing; 1 clamp for tubing; 1 perforated rubber stopper; 1 glass tube with stopcock; 1 rubber bellows; 1 glass tube in stopper; 1 piece thin walled tubing; 4 rubber balloons; 2 pieces chain; 1 adjustable small table; 2 small glass stoppers; 2 distance pieces; 1 rule and 1 sheet iron case with projecting lid and moistening flask. 52.719. Single Constituents of preceding Apparatus, see Fig. 52,718, without clamping stand j 1. 8. 0 •2 tubulated glass flasks with rubber tubing; 1 rubber stopper; 1 glass tube with stopcock; 1 small adjustable table and 1 sheet iron case with overlapping lid and with moistening flask. Cl. 842, 843, 5534, 844, 3651. 368 Equilibrium of Gases. No. >2 720- 52 730. 1 : 6. 52 734. 1 : 8. 52 733. 1 : 10. 52 735. 1 : 6. 52.720. Further Constituents of Apparatus for Experimental Measurements with Air Balloons, see Fig. 52,718 4 rubber balloons; 1 piece thin walled rubber tubing; 1 rubber ball; 1 glass tube in stopper; 2 glass stoppers; 2 distance pieces; 2 pieces chain and 1 rule. 52.721. Clamping Stand, of wood, with iron base (Retort Holder), see No. 51,110 Collodion Balloons. List No. Diameter cm Each £ 52,722 52,723 11 0.1.0 52,726 35 0.3.0 52,724 52,725 18 22 0.0.9 0.1.0 0.1.7 0.2.0 Hydrogen Generating Apparatus: see under Nos. 51,278 — 51,284, p. 213. 52,737. Hollow Cylinder, of pasteboard, for Air Balloon Experiments, after Friedr. C. G. Miiller (M. T., Fig. 105a) 52.452. Apparatus for showing the uniform Propagation of Pressure of Gases: see Figure 52,452, p. 335 52.453. - - idem, on stand and with stopcock: see Fig. 52,453, p. 335 52.730. Pressure Level, after Tb'pler, Figure, for measuring small pressure-differences (W. D., Fig. 141 [187]) 52.731. — idem, after Friedr. C. G. Miiller (M. T., Fig. 67), with T-shaped horizontal tube, with 2-colour centimetre graduation ~ii'.732. -- idem, after (Irimsehl, with air bubble in horizontal tube (Ztselir. t'. d. plivs. u. chem. U. 18, 1905, p. 199, Fig. 2) .' . 52,733. Pressure Gauge Apparatus, Figure (W. D., Fig. 138 [126]), for comparing the S. (1. !t. 0 0. 5. 0 0. 1'. (1 1. 0. 0 1. 16. (1 0. 5. 0 0. 18. 0 (I. 18. (1 62 mercury sypiiuii pressure gauge \\iin I ne \ syphon pressure gauge, with stand . . \a &er vessel prt ssure .fauge aim wuii i u e \\ a ei 1. 0. 0. 0. 1. 6. s. is. 0 0 1) 0 ,734. Pressure Gauge, for measuring the gas pressure, F i g u r e. giving pressure direct in 52,735. Pressure Gauge with 3-way stopcock, F Pressure and Vacuum Gauge, after Landolt: see i g u r e. on Fig. 50, Mi I stand a. p. . measuring to 26 120 mm i i. 1043, 850, 845, 5.V.C. Specific Gravity. Propagation of Pressure. Pressure-Measurements on Gases. 369 52739. 1 : 18. 52742. 1:8. 52743. 1 : 8. 52 744. 1 : 6. 52.737. Sensitive Syphon Pressure Gauge, after Grimsehl, based on the difference in the specific gravity of two liquids (Ztschr. f. d. phys. u. chem. U. 18, 1905, p. 199, Fig. 1) 25.738. Duplex Pressure Gauge, after Priedr. C. G. Miiller (M. T., Pig. 66), a syphon pressure gauge for two liquids, for different ranges; can be used aerostatically and hydrostatically 52.739. Open Mercurial Pressure Gauge for 2 atm., Figure, on board with graduation. 52.740. --idem, for 3 atm 52.741. Closed Mercurial Pressure Gauge, cf. Pig. 52,742, to 12 atm., with silvered graduation, with lateral tube supports with cock 52.742. --idem, Figure, without cock 52.743. Mercurial Vacuum Gauge, Figure, with 3-way cock, on polished board, with silvered metal scale 52.744. Recording Pressure Gauge, Figure, for indicating and recording from 0 — 20 kg per sq. cm When ordering please state whether the records are required to be made with hygroscopic ink or with lead pencil and whether the cylinder has to make a revolution once in 24 or once in 12 hours. .vjTi.v 400 Pieces Paper Strip for above Prices for Micromanometers quoted on application. Cl. 816, 5099, 5901,5902. £ S. d. 0.18.0 0.16.0 1. 0.0 2. 0.0 2. 6.0 2. 0.0 2. 2.0 12. 0. 0 0. 18. 0 24 370 Equilibrium of Gases. NCI. SS 746. 1:14. 52 747. 1 : 10. 58 749. 1 : 9. 52752. 1:12. 52,746. Vacuum Gauge, after MacLeod, Figure (Ztschr. f. Instrumentenkunde, 15, 1895, p. 191), for measuring high vacua. Price without mercury ............ This instrument is absolutely necessary when exhausting Geissler and Rontgen Tubes. The Oil Vacuum Pumps and Mercury Vacuum Pumps supplied by us are tested exclusively \vith this instrument. The Vacuum Gauge has a measuring bulb of 500 cem capacity and it permits of measuring high vacua th mm with accuracy. About 7 kg mercury is necessary for filling. £ 3. 15. o to 52.747. Vacuum Gauge, after MacLeod, smaller and simpler, on wall board," Figure, without mercury ................................... About 2 kg mercury is necessary for filling. 52.748. Barometrical Pressure Gauge (Differential Barometer), after Eegnault-Leduc, con- sisting of a mercury barometer and a pressure gauge having common vessel, suitable for readings with the cathetometer (Gan.-Man., Fig. 158) ............. 52.749. Barometer Tube, without graduation, with cast iron mercury cup, for Torricelli's ex- periment, Figiire (M. T., p. 116). Without mercury ............. 52.750. - - idem, with etched graduation, glass stopcock at lower end and iron cistern . 52.751. Barometer Tube, piece of Rubber Tubing and short piece Tubing (Meyer, Naturli-hre, Fig. 166) ................................... 52.752. 3 Barometer Tubes in mercury trough, Figure, with stand (M. P., HI, Fig. 236 [II, 2, Fig. 108]), for showing the difference between gases and vapours ...... 52.753. - - i d e in, tubes having etched graduation, with funnel-shaped opening and half- perforated stopcocks on the upper end, for conveniently introducing the liquids to be evaporated .................................. 1. Hi. o 8. o. o 0. .'!. o <>. ••<.<> 0. 2. 6 1. Hi. n 2. it. n (.'I. 967, 968. 853, 856 No. S3 764. Vacuum Gauges, Pressure Gauges, Barometer Tubes. 371 52 754. 1 : 7. 52756. 1:10. 52 758. 1 : 10. 52762. 1:15. 52.754. 4 Barometer Tubes, of 15, 12, 8 and 6 mm width, Figure, for showing that the height of the barometer is independent of the width of the tubes, but that the meniscus influences the reading to a greater extent in the case of narrow tubes than in the case of wide; with etched graduation (in millimetres at the upper end) and one iron trough, iron stand with ribs for removing the tubes laterally One of the tubes is provided underneath with a stopcock for securing ease of manipulation in the general experiments on the Torricellian vacuum. 52.755. - - idem, without graduation 52.756. Demonstration Barometer Tube, after Kolbe, Figure (Ztschr. f. d. phys. u. chem. U. 6, 1893, p. 31), of glass, with two stopcocks and glass vessel "'-.757. - - idem, with one platinum electrode in the upper part . . 52,758. Barometer Tube, with 80 cm long iron tube vessel, .Figure .">:.'. 759. -- idem, the glass tube, however, being fitted above with stopcock and etched graduation 52,700. Tripod Stand, of wood, for barometer tubes Nos. 52,758 and 52,759 :>L'.761. Barometer Tube, with iron tripod stand (cf. M. P., I, Fig. 472 [513]), cf. Fig. 52,762; the tube graduated, without tube holder and index, and without cock :>L'.762. -- idem, with Tube Holder and Index, Figure 52,763. Duplex Barometer, suitable for explaining the Syphon (Fr. phys. Techn. I, 2, Fig. 2558), with one vessel "•u.764. - - idem, with two vessels, for two liquids (Fr. phys. Techn. I, 2, Fig. 2559, see also Ztschr. f. d. phys. u. chem. U. 14, 1901, p. 347) £ s. d. 2. 2.0 1. 12. 0 0. 15. 0 0.18.0 0.14.0 1. 0.0 0. 8.0 1.10.0 1.16.0 0. 8.0 1.10.0 Cl. 857, 3343, 854, 4538. 24* 372 Equilibrium of Gases. No. 52 765 - 52 766. 1 : 14. 52767. 1 : 12. 52774. 1 : 10. 52776. 1: 10. 52777. 1 : 10. 52.765. Duplex Barometer, after Kleiber, with two tubes connected under the mercury level | (Fr. phys. Techn. I, 2, Fig. 2560; Ztschr. f. d. phys. u. chem. U. 14, 1901, p. 247. Fig. 2) 52.766. Apparatus for the Torricellian Experiment, after Dechant, Figure, can also be used as an open or a closed Manometer The U-tube is filled with a sufficient quantity of mercury, and for demonstrating the baro- meter, the apparatus, with stopcock open, is inclined to the right until mercury flows out of the cock; the cock is then closed and the apparatus placed upright. 52.767. Demonstration Barometer, after Schulze, Figure, with 3 glass stopcocks . . . Suitable for showing air-pressure and Marietta's Law. 52.768. Experimental Barometer, after Friedr. C. G. Miiller (M. T., Fig. 84), can also be used as a Vacuum Gauge, with plain millimetre and centimetre graduation 52.769. Simple School Model of Barometer, with Fortin Vessel (Kleiber, Lehrb. f. Gymnasien. Fig. 114), without mercury 52.770. --idem, of Syphon Barometer, with U-tube (Kleiber, Lehrb. f. Gymn., Fig. 115 a), without mercury 52.771. Barometer, simple, on board with milk glass scale 52.772. Barometer, English form, Figure, ivory scale with vernier 52.773. Standard Barometer, after Regnault (Gan.-Man., Fig. 141), for rending with the catheto- ineler, with tube 2.5 cm wide and iron cistern 52,774. Barometer, on finely polished board, Figure, the sight vane adjusted by rack and pinion, with 2 thermometers 52,775. - - idem, sight-vane without rack motion £ s. d. 0.12.0 1. 2.0 1.10.0 1. It), o 0. is. o 0.12.0 0.12.0 2. d. d 8. d. II 2. d. d 1. ID. It Cl. 5363, 852, 859, 5061, 860, 5339. Xo. 52 785. Barometers. 373 52 778. 1 :8. 52779. 1: 10. 52782. 1: 9. 52 783. 1: 9. 52785. 1: 10. 52.77«. Syphon Barometer, after Brunn, Figure, can be used for accurate readings with £ s. d. the cathetometer (Fr. phys. Techn. I, 2, Fig. 2552) 1.14.0 The upper part of the tube is exhausted with the vacuum pump, the cock being then closed and the apparatus tilted until the mercury has ascended into the upper vessel. When the instrument is again placed upright the mercury divides and an absolute vacuum is formed in the main tube. If air should collect in this later it can be shifted into the upper vessel quite easily by tilting. .")!.'. 777. Syphon Barometer with Glass Verniers and graduations on glass, Figure, the graduations being insensitive to the action of moisture 10. 0. 0 52,778. Syphon Barometer with sliding wood rule, Figure, on black, polished board, with ebonite seal and two sighting vanes 1. 12. 0 5.!. 779. - - idem, in case, portable, Figure, for measurements in mines, etc.; on black, polished board, with adjustable wood rule, ebonite seal, sight-vanes and with thermo- meter with Centigrade graduation 2. 6. 0 52,780. Syphon Barometer, with sliding metal rule, otherwise as No. 52,778 2. 0. 0 .")!', 78 1. Syphon Barometer, with etched graduations on the limbs, with 2 adjustable sight vanes 1. 10. 0 52,782. Station Barometer, Figure, Eule adjustable by rack and pinion, verniers read with magnifying glasses 8. 0. 0 52.7tf.'i. Syphon Barometer, after Krajevitch, Figure, with adjustable metal scale, with rackwork and vernier, with cock on the short limb, plummet and thermometer graduated in Vs0 C., in case | 5. 0. 0 Air bubbles can easily be forced into the extension of the long limb by tilting. 52.784. - - idem, simpler, scale adjustment without rack 4. 0. 0 52.785. Syphon Barometer, with adjustable Barometer Tube, Figure, with metal scale, vernier and thermometer, the scales being silvered 3.10.0 Cl. 861, 3344, 862, 5439, 5393. 374 Equilibrium ol Gases. N.I. :V2786 — \s 52 786. 1 : 7. 52 787. 1 : 9. 52 788. 1 : 7. 52 790. 1 : 7. 52,786. Fortin Station Barometer, Figure, in metal case, tube 19 mm internal width, vernier reading to 1/,0th mm and movable with rack; reading of vernier and level facilitated by mirror illumination. The thermometer is in direct contact with the barometer tube and can be read from the outside. The instrument is suspended on a hook and can be centred at the lower end . .">!'. 787. -- idem, with tube 12.5 mm wide, Figure 52.788. Travelling and Altitudinal Barometer, after Fortin, F i g u r e, with tube 10 mm width, vernier giving Vioth """• with thermometer, Stand and Universal Suspension, also leather case 52.789. -- idem, as Station Barometer, on -wood board, Figure (i. o. o 1 s. (1. IS. 10. 0 10. 0. (I 7. 10.11 01. 865. 866, 867. 868. 869. No. 52 796. Station Barometers. Aneroid Barometers. 375 52791. 1:3. 52 792. 1 : 4. 52 794. 1 : 4. 52 795. 1 52 796. l 52.790. Travelling ana Altitudinal Barometer after Gay-Lussac, Figure, syphon baro- meter, with two verniers, giving 1/ioth mm, with thermometer, stand, and universal suspension and with leather case 52.791. Bourdon's Tube, on stand, Figure, with pointer and scale, for placing on the vacuum pump, for explaining the principle of the Aneroid Barometer 52.792. Aneroid Barometer (Holosterical Barometer after Vidi), Figure, excellent mecha- nism, mounted open, 100 mm scale diameter, with glass plate, glass bell and rubber tubing with mouthpiece If the air under the glass globe is compressed or rarified by blowing through or applying suction to the mouthpiece, the barometer gives these variations. 52.793. - - idem, scale 130 mm 52.794. Demonstration Aneroid Barometer for the Vacuum Pump, Figure 52.795. Demonstration Aneroid Barometer, after Weiler, Figure 52,796. Demonstration Aneroid Barometer, Figure, for suction, with rubber tubing and mouthpiece, covered by glass bell, can be used horizontally and vertically The instrument works very well and can be recommended. Cathetometers for accurately reading Barometers: see Nos. 51,463—51,466, p. 224. £ s. d. 7.10. 0 1. 2.0 2. 4.0 2.10. 0 2.10.0 2.10. 0 1.10.0 C]. 870, 872,3345, 4699, 873. 376 Equilibrium of Gases. No. 52 797 52 802. 1 : 3. 52 804. 1 : 2. 52810. 1 : 12. 52.797. Levelling Barometer, after Goldschmidt, Figure, for altitudes to 5000 m, accurate t to approximately 2 m. with comparison table and thermometer, in case with carrying straps 5. 52.798. - - idem, accurate to approx. 1m 52.799. Altitudinal Barometer, Figure, with rotary scale, for altitudes from 0 to 2500 in 1 52.800. - - idem, finest construction, compensated and gilt, Figure, in case, to 5000 m 52.801. - - i d e m, with compass on back :<. 52.802. Altitudinal Barometer, Compass and Thermometer, in case, Figure 2. 52.803. -- idem, smaller, watch-pocket form and finest construction 4. 52.804. Aneroid Barometer, Figure, simple, in metal ease, with open mechanism of 9 em scale diameter 0. 52.,sor>. Good Round Pattern Barometers, in metal ease or in wood frame. Price according to to construction i 0. 15. 0 1. When ordering kindly state prin . I 'I. S74, S7.-I, JT0, -7 877, 878, 884. 0. 0 10. 0 10. 0 15. 0 Ki. 0 , 10. 0 0.0 10. 0 15. 0 Xo. 52812. Altitudinal Barometers, Barographs, Boyle's Law. 377 52 808. 1 : 3. sol 52809. 1:7. 52812. 1:7. 52811. 1:10. 52.806. Metal Barometer with Bourdon Tube, Figure, 130 mm diameter, very sensitive 52.807. - - idem, with scale 200 mm in diameter 52.808. Aneroid Barograph, Figure, with 8 boxes, 8-day mechanism 52.809. --idem, Figure, highly sensitive, with large deflection combined with high accuracy This instrument, is employed for investigating sudden fluctuations of pressure attendant on the occurrence of storms, cyclones and meteorological phenomena generally. As an amplitude of 10 or 25 mm is recorded for 1 mm pressure-difference, an estimation to 0.01 mm can be made. 52.810. Recording Mercurial Barometer, Figure, a very accurately indicating instrument Deflection on the drum amounting to 3 mm for every 1 mm of the mercury column. 52.811. Boyle's Law Apparatus, Figure, after Feilitzsch, as altered by Weinhold (W. D., Fig. 139 [127]), 2.2 m high 52.812. --idem, with the addition of a Glass Vessel, Figure (W. D., Fig. 344 [324]), to enable the apparatus to be used for determining the coefficient of expansion of gases at constant volume or as an Air Thermometer CI. 880,881, 886, 885. £ S. d. 1.10.0 1 2. 0. 0 6. 0. 0 17.10.0 15. 0.0 2.14.0 3. 6.0 378 Equilibrium of Gases. No. 52813 — 52813. 1 : 14. 52814. 1:18. 52 815 A. 1:14. 52 815 B. 1 : IT, 52.813. Boyle's (Mariotte's) Law Apparatus, after Friedr. C. G. Miiller, Figure (Ztschr. f. d. phys. u. chem. U. 16, 1903, p. 18; M. T., Fig. 85), can also be used as an Air Thermometer The apparatus is for use in conjunction with a vacuum pump. It is possible by this arrangement to generate -over -pressures to 2 atm., while still keeping the construction of the apparatus of a short form. In addition there is the advantage that the pressure gauge tube can be made entirely of glass without the use of rubber connections and that valves can be omitted. The horizontally arranged measuring tube is connected by a thick -walled rubber tube with the manometer tube by means of a 3-way cock, which also admits of connecting up to the vacuum pump by a separate attaching tube. 52.814. - - i d e m, after Pfaundler, Figure, 2.2 m high, with coloured centimeter gra- duation and with adjustable glass rule, 1 m long, resting in the centre of the rail, the glass rule, having etched millimetre graduation. Apparatus can also he used as an Air Thermo- meter 52.815. Boyle's (Mariotte's) Law Apparatus, large pattern, 2.8 m high, Figure A, with glass vessel and accessories, Figure .B, the use of the latter enabling the apparatus to be used as an Air Thermometer 52.816. Boyle's (Mariotte's) Law Apparatus, after S/.ekely, Figure, with spring pressure 4. d. d (i. o. (i 7. 0.0 gauge and small force pump The tubes are suitable for high pressure, lieini; constructed of Jena glass and provided with steel Cl. 837, 888, 889, 890. 14. 0.0 I, 890. No. 52821. Boyle's (Mariotte's) Law. 379 i 52 816. 1 : 20. 52817. 1:9. 52818. 1:12. 52820. 1:12. 52 8J51. 1 : 1U. stopcocks. The scale is visible at a considerable distance, used to 2.5 atm. With both limbs the apparatus can be 52.817. Boyle's (Mariotte's) Law Apparatus, after Huber, Figure, on iron stand and wood board, with two-coloured scale; can be used as an Air Thermometer The pressure tube has a scale 1.10 m long with millimetre graduation and with black and white centimetre graduation visible at a considerable distance. The short arm has a graduation on glass, contains a thermometer closed by the upper aperture which must be pocked with mercury, and is en- closed in a cylinder of large diameter so that a uniform temperature of the gas to be investigated is maintained by a current of air or the like. 52.818. Boyle's (Mariotte's) Law Apparatus, Figure, small pattern, with fixed glass tube, 1 stopcock on the lower end, 1 stopcock on the short limb; scale with coloured gradua- tion which is easily visible; on iron stand 1.1 m long 52.819. - - idem, with fixed glass tube, with stopcock on the short limb r>L'..s20. --idem, on polished board, with figured graduation, Figure, without glass stopcock (Gan.-Man., Fig. 151, 152) .">_'. S21. - - idem, after Hugh M. Browne, Figure, for pressures to 10 atm., with spring manometer and easily visible scale The apparatus is easy to manipulate, is very substantially built and possesses steel stopcocks. The pressure is generated by leading in compressed air. £ s. d. 2. 0.0 1. 4.0 1. 0.0 1.10.0 4. 0..0 See also the Apparatus after Schafiers, Schneider and Lermantoff, on pp. 365 and 366, also Barometer Tubles Nos. 52.758—52,762, p. 371. Cl. 894. 3346, 4776, 892, 893. 380 Equilibrium ol Gase?. X... .V.' v.'-j 52 823. 1 : 7. 52 824. 1 : 10. 52832. 1:7. 52834. I : £ 0. .. (1. 1. (i 52.822. Air Thermometer, for proving Mariotte's Law (Kleiber, Lehrb. f. Gymn., p. 107) . 52.823. Volumnometer, after Eegnault, Figure, for volume determinations on pulverulent and porous bodies; all stopcocks of steel (M. P., I, Figs. 488 — 492 [529—533]) . . . 3. in. o 52.824. - - idem, after Paalzow, Figure, with vessel which can be closed by a ground glass lid (Fr. phys. Techn. I, 2, Fig. 2764 [I, Fig. 291]; W. u. E. phys. Prakt,, Fig. 51) :>. o. o 52.825. Stereometer, after Say, Figure, for determining the volume and density of pul- verulent bodies (M. P., I, Fig. 486 [527]) 0. 6. 0 52.826. Bathometer, of glass (W. D., Fig. 157 [144]) 0. 5. 0 52.827. Vestal Sieve 0. 5. 0 52.828. Magic Jug 0. LO 52.829. Tantalus Cup, Figure (Gan.-Man., Fig. 204) 0. 1. 8 52.830. Magic Pitcher D. 9. 0 52.831. Magic Tun, Figure I. I." 52.832. Magic Funnel, Figure o. l.o 52.833. Inverted Float, after Weinhold (W. D., Fig. 144 [131]) o. :;. u 52.834. Mariotte's Bottle, Figure, with 3 emission apertures o. Hi. o 52.835. - - i d e m, after Friedr. C. G. Muller (M. T., Fig. 72) 0. 6. 0 52.836. Mariotte's Bottle, with metal fittings, Figure (Gan.-.M;m.. Fijr. I'.io) o. i:>. o 5L!.X37. Large Mariotte Bottle, 1 m high, Figure, with gnidiution and n>»-iil;iting dis- charge cock 3. lo. u 52,838. Syphon, of glass, Figure, 500 mm | 0. 0. 6 (1. 3333,897, 898. 895, 5389, 3955. 334U. X.i. :.2856. Effects of Air-pressure. Volumnometers. Syphons. Heron's Ball. 381 52849. 1:6. 52852. 1:5. 52838. 1:6. 52840. 1:6. 52837. 52856. 1:4. £ s. d. 52.839. Connecting Syphon (M. T., Fig. 88) ...................... 0. 2. 0 52.840. Plunging Syphon, of glass, Figure ..................... 0. 0. 6 52, 841. Pipette (Luhme's), with gutta-percha slab . .................. 0. 0. 9 52.842. Syphon for poisons, of glass, with stopcock, Figure ............. 0. 3. 0 52.843. - - i d e m, without stopcock ......................... 0. 2. 0 52.844. Poison Syphon for easily flowing liquids, for use by blowing (W. D., Fig. 149) . . 0. 3. 0 52.845. Equal-limb Syphon (W. D., Fig. 151 [138]) .................. 0. 3. 0 52.846. Syphon (Weinhold's) (W. D., Fig. 152 [139]), with constricted tube ....... 0. 2. 0 52.847. Discontinous Syphon (W. D., Fig. 164) .................... I 0. 5. 0 52.848. Syphon Apparatus, after Schulze (Fr. phys. Techn. I, 2, Fig. 2561) ....... 2. 0. 0 52.849. Circulating Syphon, Figure (M. P., I, Fig. 530) ............... 0. 9. 0 52.850. Apparatus for showing the circulation of the blood, 35 cm ........... 0. 10. 0 52.851. -- idem, larger, 75 cm ........................... 1. 5. 0 52.852. Heron's Ball, simple, with glass cock, Figure ................ 0. 3. 0 52.853. Small Heron's Ball, with brass cock, Figure ................ 0. 5. 0 52.854. Heron's Ball, screwed, with stopcock ..................... 0. 12. 0 52.855. — i d e m, with rubber bellows ....................... 0. 16. 0 52.856. Heron's Ball with Force Pump, Figure, constructed entirely of brass and glass; height: 30 cm ................................. 2. 0. 0 Cl. 899, 4862, 904, 3350, 901,902,900,903,905. 382 Equilibrium of Gases. No. 52 857 52866. 1:8. 52 869. 1 : 9. 52 860. 1 : 10. 52863. 1:10. 52 868. 1 : 5. 52.857. Heron's Ball with Force Pump, entirely of metal, with spring pressure gauge, F i g u r-e 52.858. Heron's Fountain, of glass, with base, Figure 52.859. Heron's Fountain, with wood stand, Figure 52.860. Heron's Fountain, large, Figure, with metal mounting, durably constructed, can be taken to pieces (Gan.-Man., Fig. 200) 52.861. Intermittent Fountain, of glass. Figure (W. D., Fig. 155 [142]) 52.862. - - idem, with iron stand 52.863. -- idem, large pattern, witli metal mounts and metal basin, Figure . . . . 52.864. Cartesian Diver, in cylindrical glass vessel with rubber bung 52.865. - - idem, after Weinhold (W. D., Fig. 156 [143]), with glass cylinder 52.866. Cartesian Diver, Figure, in glass cylinder with metal screwed union and force pump Cl. 4'J79, 906, 907, 908, 5835, 910, £ S. 1. 10. 0. 8. II. IS. 2. 111. o. ;;. 0. 6. 1. 1 I. 0. 2. (I. 4. (I. 12. 911.913, 912. No. 52 875. Heron's Ball, Heron's Fountain, Suction Pumps, Force Pumps. 383 \ 52 870. 1 : 5. 52875. 1:9. 52 873. 1 : 6. 52 874. 1 : 4. 52.867. 6 Glass Tubes, for setting up as a .Cartesian Diver (M. T., Fig. 69) 52.868. Model of a Suction Pump, Figure, with movable piston and movable valves . 52.869. Model of a Suction Pump, of glass, Figure 52.870. - - i d o m, with metal stand, Figure 52.871. --idem, of glass and metal, Figure 52.872. Model of a Suction Pump, large and massive pattern, Figure, with brass valves visible at a distance, with iron stand; total height: 67 cm; diameter of cylinder: 57 mm 52.873. Model of a Suction Pump, French form, Figure, finely constructed 52.874. Suction Pump, with electric motor drive, Figure For 4-volt D. C. current consumption = 1 ampere. 52.875. Model of a Force Pump, of glass, Figure £ s. d. 0. 1.0 1. 4.0 0. 3. 0 0.12.0 1. 8.0 3. 4.0 3.12.0 2. .0. 0 0. 3.6 Cl. 914, 915,916, 917,923,5884. 384 Equilibrium of Gases. NU. .V2876 — 52 876. 1 : 5. 52 877. 1:5. 52 879. 1 : 6. £ s. (1. 52,87<'.. Model of a Force Pump, of glass, with metal stand, Figure 0. 12. o 52,877. -- idem, nf glass and metal, larger and stouter construction, Figure . . . . 1. It'.. (I r>2.H78. --idem, larger and stouter construction, Figure, with brass valves visible at a distance, with iron stand; total height: 67 cm; diameter of cylinder: 57 mm . :>. 12. 0 ci. nin. a-.'i, No. 52883. Force Pumps, Fire Engines. 385 52881. 1:5. 52 882. 1 : 6. 52 883. 1 = 8. j2,879. Model of a Force Pump, French form, Figure, of gla.-s and metal, finely con struoted 52,880. Model of a Centrifugal Pump with glass ascension pipe, of metal. F i g u r e, mounted with drive on wood board £ s. d. 4. 4. 0 5. 0. 0 52,005. Model of the Centrifugal Pump, with visible mechanism, for the whirling table, after Hurt!, sec Xo. 52.005 on page 282 2.15.0 52.881. Model of a Fire Engine, of glass, in metal stand, Figure 1. 2. 0 52.882. -- idem, of metal and glass, Figure 2. 11. o 52.883. Model of a Fire Engine on Carriage, Figure 3. r.'.o Cl. 924, 925, 92G, 926 ». 386 Motion of Gaseous Bodies. No. 52884 rrj-Jj) 52 886 B. 1:5. 52887. 1:10. 52 885. 1 : 8. 52 886 A. 1 ; 8. 52888. 1 : 10. Motion of Gaseous Bodies. Piston Vacuum Pumps of various Systems. I 8. (1. 52.884. Small Stopcock Vacuum Pump, on iron base, with obliquely inclined cylinder 28 nun internal diameter and 230 mm length, glass plate 140 mm diameter, piston for hand motion, without receiver ............................ 2. 0. 0 Largest Receiver for use with above: No. 53 009 ..................... 0. 2. n 52.885. - - idem, mounted on massive iron screw clamp, Figure, barrel 30 mm internal diameter, 300 mm long, piston for hand motion, glass plate 140 mm diameter (M. T. p. 121 ) i". <>. o 52.886. - - i d e m, larger, Fig. 52,886 A, on massive Iron Base, with barrel 32 mm internal diameter and 280 mm length, glass plate 180 mm diameter, with one iron Screw Clump. Fig. 52,886 B, for firmly clamping to the table, without receiver ......... 3. 0. o Largest Receiver for use with above: No. 53,011 ..................... d. 3. o .")•_'. SX7. Vacuum Pump, Figure, on heavy iron base, piston movable by rack and pinion. cylinder 40 nun diameter, 290 mm long, glass plate 200 mm diameter, steel cock, with large jack, to enable it to be turned even when the tallow is hard, with S^iron Screw Clamps, see Fig. 52 886 B, without receiver ............. •* • • 6. 0. 0 The freezing experiment with water ;uid sulphuric acitl can lie carried out with this Vacuum Pump: a vacuum up to 4 mm mercury column is attained in a receiver containing up to 2 litrc>. - Largest receiver for use with almve: No. ,'53,(ll-2 ....................... 0. 4. 0 .Vj.xss. Vacuum Pump, Figure, with cylinder 60 mm internal diameter and :'>5:!. Oil ..................... O. .">. (i It is. however, advisable to select the next smallest. No. ."i3.OI3 .............. 0. 4. 8 52.XSH. idem, with Barometer Gauge attached, with two iron Screw Clamps, FL<. :,:! s,s(i 1! . 9. n. Water Air Pumps: sec pp. L'-J •_•;. ' 'i :;• 9J9, NIP. -V_'-!H. Stopcock Vacuum Pumps. 387 52 893. 1 : 4. 52894. 1:5. 52 892. 1 : 4. £ s. d. 52,890. Device for considerably ratifying the ah in the clearance before each stroke. Extra price 1. 4.0 Can only be used for Pumps Nos. 52,887, 52,888 and 52,889. 52,893 . Stopcock Vacuum Pump with 2 Barrels, Figure, barrels 60 mm internal diameter and .'?.">() mm length, with glass plate 280 mm diameter, with Grassmann cock for entirely obviating the influence of clearance; without receiver This Vacuum Pump rarifies twice as quickly as a single-barrel one and exhausts up to 1.5 or 2 mm. Largest Receiver for use with above: No. 53,015 52, 892. Model of a Babinet Vacuum Pump Stopcock, F i g u r e, of wood 52,893. Model of a Grassmann Vacuum Pump Stopcock, F i g u r e, of wood 52.X91. Vacuum Pump after Bianchi, Figure, with Glass Barrel, double-acting, with steel valves placed outside the barrel, with sleel Babinet stopcock, very nicely constructed, with neat, firm iron base; Glass Plate 280 mm diameter on special tripod, with Baro- meter Gauge, 300 mm high, finnly attached; connecting tubing screwed at both ends The Vacuum I'limp gives 4 mm tor large and 2 mm exhaustion for small receivers in an extra- ordinarily >lmrl -|i;n-c of time. The valves — contrary to (he original construction described in most text-books — being place:! outside the cylinder can be very easily cleaned. Price is exclusive of Re- ceivers. Largest Receiver for use with above: No. .">:!. o|.~, 15.10.0 0. 6. 6 1. 0. 0 1. 0.0 31. 0. 0 i). 6. 6 Cl. 934, 996, 5894, 995. 388 Motion of Gaseous Bodies. NCI. - 52835. 1 : 12. 52898. 1:7. 52900. 1 : fl. iCtli. !ISS. '.i:i'i. '.mi. XM. .VJ MOM. Stopcock Vacuum Pumps. 389 \ 52 896. 1:11. .">:_'. sl.~> 55.0. 0 0. (i. (i The pump is driven by a '/3r(l II. I'. Direct Current Motor. The following are included in the price: Starting Rheostat, 1 double-pole Switch and 1 Plug Box with plug. When ordering, kindly state kind of current and voltage. If this is not given we supply the motor for a pressure of 110 volts D. ('. i, *!)(>. Vacuum Pump aftev Deleuil, Figure, with glass ban-el 90 mm internal diameter and 320 mm height, metal piston with guide passing freely in the cylinder, with Babinet cock, with neat iron stand; can be used for evacuating and compressing; all cocks of steel; Glass Plate 280 mm diameter on special tripod, with Barometer Gauge 300 mm high Price exclusive of Receivers. Largest Receiver for use with above: X<>. .•>:!.<)].-> 33.0. (I -,*97. Vacuum Pump with 2 Vertical Glass Barrels, Figure, 55 mm internal diameter and 220 mm height; with Glass Plate 250 mm diameter and Barometer Gauge 300 mm high, with steel valves fitted outside the cylinder and with steel Babinet cock; on polished Oak Table 20. o. o Price exclusive of Receivers. Largest Receiver for use with above: No. ,">:!. 014 It is advisable, however, to choose the next smallest. No. 53,013 VJ.S98. -- idem, on low oak block, Figure 18.0.0 ">2,S!t!i. -- idem, with glass barrels 50 mm internal diameter, 200 mm high, Barometer Gauge 200 mm high 15. 0. 0 ">2.!M>o. Model of a Double Barrel Vacuum Pump, Figure, of wood, pasteboard and metal, showing plainly the play of the pistons, valves and rods, with Babinet cock .... 3.0.0 Cl. 937. 390 Motion of Gaseous Bodies. No. iil'DOl — 52 901. 1 : 10. 52 903. 1 : 10. High -Vacuum Pumps with Oil-packed Piston, Kohl's System, German Patent. The advantages of these Oil Vacuum Pumps are that they are very easy to work, generate a high vacuum, arc rapid in their action, and can be run in a simple, convenient and clean manner without any special preparation. The Oil Pumps yield in a few minutes what it takes the Sprengel mercury vacuum pump 1 hour to attain. These pumps are therefore peculiarly adapted both for de- monstration purposes and specially for rapid working in laboratories. We would remark that in all pumps for which a vacuum of 0.0014 mm mercury column is guaranteed, a vacuum of 0.0008 mm can be reached. Every Oil Vacuum Pump is accompanied by a Test Certificate. The test is made in our simps with the MacLeod Vacuum Gauge having a 500 com measuring bulb (see No. 52,746). If, in the case of Pumps fitted with Electric Motors, a motor is desired for a different kind of current or a different voltage from that quoted, a corresponding change in price is made. When ordering pumps with electric motor drive, the type of current, network voltage (and in the case of alternating or three-phase current, the freqency also) should be stated on each occasion. Complete description sent if desired. £ 8. tl. 52.901. Vacuum Pump with Oil-packed Piston and oil non-return valve, Kohl's system, German Patent, Figure, with hand lever, with 1 barrel 40 mm internal diameter, stroke 160 mm; with Plate 180 mm diameter, without receiver 5. u. I) Trie pump exhausts to ' .„ mm. Largest Receiver which can be used: No. 53011 o. :). o 52.902. --idem, with Fly- Wheel, for Hand and Power Drive, cf. Fitr. :>L'.9d9 (i. 10. o .">L'. 903. Vacuum Pump with Oil-packed Piston aiul oil non-return valve, Kohl's system, German Patent; larger, Figure; with Hand Lever, with 1 Barrel .~>d mm internal diameter; Stroke Itid mm; without Plate or Receiver <>. d. 0 T/ie pump exli;msl< id ' I0th mm. rtL',904. - - i (1 e m, with Hand Lever, with Plate -40 mm diameter, and Barometer Gauge 200 mm high, Figure s. 10. 0 Largest Receiver that ran be used: No. .">:!. U|:J I). I.'. I :.L'.90.-). - - idem, with Fly-wheel, for Hand and Power Drive, \\ithoul Plate, cf. Fig. .VJ,909 7. Id. 0 r»ii,9d<;. -- idem, with Fly-wheel and with Plate 240 mm diameter and Barometer-Gauge 200 mm Iii-h . . . Id. d. d :.L'.'.id7. Vacuum Pump with Oil-packed Piston and oil non-return valve. Kohl's system. German Patent. Figure, with Hand Lever, larger than preceding; with 1 P.arrel (Id mm internal diameter; Stroke 190 mm; without Plate S. Id. d The puiiiii exhaust*- to ' ,„"> M. 911. !U-.' Xci. .V-MU1. High -Vacuum Pumps with Oil-packed Piston, Kohl's System. 391 52909. I ; 10. 52 904. 1 : 10. .•ff-vv, r ) ii* ' 52 907. 1 : 9. 52911. 1:10. 52,908. Vacuum Pump with Oil-packed Piston and oil non-ivtum valve, Kohl's sysiciii. (Icnnaii £ * <1 Patent; with Hand Lever and with Plate 240 mm diameter and Barometer Gauge 200 mm high 11. 0. 0 ">2, !!()!». -- idem, with Fly-wheel, for Hand and Power Drive, without Plate, Figure 10. 0.0 2,910. - - idem, with Fly-wheel and with Plate 240 mm diameter and Barometer Gauge 200 mm high . . . . ' 12.10.0 Largest Receiver for use with above: No. 53,013 0. 4. 9 "»2.!i 1 1 . - - idem, driven by a ' /6th H. P. Electric Motor with worm gearing, motor for 110 volt Direct Current, with Starter, without Plate, Figure 22 10.0 Vacuum Pumps No. 52,903—52,910 are specially intended for rapid work in laboratories. I 'I. 1)43, 3B52, 4711, 4713. 392 Motion of Gaseous Bodies. No. 52915. 1:10. 52 917. 1 : 8. £ s. ,!. 52.012. Vacuum Pump as No. 52,911, with 220 volt I). ('. Motor 2:;. 5.0 52.013. - - i d e m, with Plate 240 mm diameter and Barometer Gauge 200 mm high; 110 volt D. C. Electric Motor . . . , 26. 0. 0 Largest Receiver for use with above: No. 53,013 li. 4. '.I 52.014. --idem, with 220 volt 1). f\ Electric Motor 25.15.0 52.015. Duplex Vacuum Pump with Oil-packed Piston and oil non-return valve. Kohl's system, German Patent, Figure, with Hand Lever. 2 Barrels of the same size 50 mm in iuiernal diameter; Stroke 120 mm, for exhausting glow lamps and X-Ray Tubes as well as for rapidly obtaining a vacuum, without Plate 17. Hi. n 52,016. - idem, with Plate 240 mm diameter and Barometer Gauge 200 mm high . . 20. 0. o Largest Receiver for use with above: No. 53,013 0. 4. '.I 52.017. Duplex Vacuum Pump with Oil-packed Piston and oil non-relurn valve. Kohl's system, del-man Patent, with Fly-wheel and Clearing, Figure, for Hand and Motor Drive. with 2 Harrels of same si/,e of 50 mm internal diameter; Stroke 120 mm; without Plate 24. Hi. 0 Tin- pump e\liau>is to 0.0014 mm. To faeililale the working of the Pump, especially when eoiimiencing to pump, we have provided the pump with a toothed wheel gearing, as experience shows that it is much easier lo expend a small amount ol eueruy in turning a wheel SO —Km times a minute than to turn 0 •' times a minute with fi correspondingly larger amount of energy. Tue cog wheels are cased in. 52.018. -- idem, with Plate 240 mm diameter and Barometer Gauge 200 mm high . . 27. o. o Largest Receiver for use with aliove: No. .Vt. (>]'•> «. I. fl 52.'.»M>. Duplex Vacuum Pump with Oil-packed Piston and oil non-return valve. Kohl's system, (lermaii 1'alenl, Figure, with Fly-wheel, without gearing; arranged for Hand and .Motor Drive; with 2 Harrels of equal si/e of 50 mm internal diameter; stroke 120 mm; without Plate 22.10.0 The pump exhausts to 0.0014 mm. 52.020. - - i d e in. with Plate 240 mm diameter and Barometer Gauge 200 mm Largest Receiver for use with ahove: No. .">.'!. Ol.'J ' 25. 0. 0 o. i, '.i 52.021. - - i d e m, driven by a ' ;' ' H. P. 110 volt Direct Current Electric Motor. F i g n r e, On table with polished oak top and iron frame; without Plate 15. o. O The air pump is mounted on a talile with polished oak top and iron frame. The shelf under- neath, as seen in the illustration, carries the ' ,rd [| I>. |>. r. Klccttic Motor fitted with worm The starling rheostat as well as thf necessary Mvilehgear- are mounted on the talile top. il. 'Jit, 4712. High Vacuum Pumps with Oil-packed Piston, Kohl's System. 393 52 919. 1:9. 52921. 1 : 13. The price includes the jirce.-soi 'if- illustrated — transmission, belt, motor, starter, .-witches and lend* mounted on the table. If desired we can supply an A. ('. or a :i-phase Motor for driving, the price beinji correspondingly increased. 52.022. - - i (1 c in, with 220 volt Direct Current Electric Motor 52.023. - - i (1 c in, as No. 52,021, with Plate 240 mm diameter and Barometer Gauge 200 mm liiji'li, with 110 volt I). C. Electric Motor - . . . 52.024. — idem, with 220 volt B.C. Electric Motor 52.025. Duplex Vacuum Pump with Oil-packed Piston and oil non-return valve, Kohl's .system, German Patent, for Motor Drive, larger, internal diameter of Barrels, 75 mm; Stroke Kid mm; without Motor and Plate The pliTiip exhausts lo 0.0014 mm. .'.!)2ii. -id e m, with Plate 280 mm diameter and Barometer Gauge 300 mm liijrh . . Largest Receiver for use with above: No. 53,015 £ s. d. 46. 0.0 "•2.027. -- idem, driven by a ' , H. P. Direct Current Electric Motor for 110 volts, on table with polished top and iron frame, without Plate, cf. Fig. 52,021 i,02.s. -id e m, with 220 volt D. C. Klectric Motor "•2,020. -- idem, with Alternating Current Asynchronous Motor and belt releasing device "•2.030. - - i d e m, with Plate 280 mm diameter and Barometer Gauge 300 mm hijdi, with 110 volt D. C. Electric Motor "•2,031. -- idem, with 220 volt Direct Current Electric Motor vj,!»32. - - i d e m, with Alternating Current Asynchronous Motor and belt releasing device 47. 48. 27. 31. 0. 50. 51. 53. 54. 58. 10.0 10.0 10. 0 0.0 0.0 5. 0 It. Ii 10. 0 15.0 10. 0 Cl. 04ia, 47H. 394 Motion of Gaseous Bodies. -\;i. .VJ933 — 52946. 1:4. 52949. 1:9. 52.933. Duplex Vacuum Pump with Oil-packed Piston and oil non-return valve, Kohl's System, C.erman Patent, for Motor Drive, still larger than preceding; internal diameter of Barrels, 100 mm; Stroke 220 mm; without Motor or Plate The pump exhausts to 0.0014 mm. 52.934. - - i d e m, with Plate 320 mm diameter and Barometer Gauge 300 mm high . . Largest Receiver for use with above: No. 53,016 . .' 52.935. - - idem, driven by a 3/4 H. P. Direct Current Electric Motor for 110 Volts, on table with polished top and iron frame; without Plate, cf. Fig. 52,921, p. 393 . . . 52.936. - - i d e m, with 220 volt D. C. Motor 52.937. - - idem, with Plate 320 mm diameter and Barometer Gauge 300 mm high, with 110 volt D. C. Motor Largest Receiver for use with above: No. 53,016 52.938. --idem, with 220 volt D. C. Motor 52.939. Duplex Vacuum Pump with Oil-packed Piston and oil non-return valve, Kohl's system. (Jerman Patent, for Motor Drive, larger than preceding; internal diameter of Hariris. 125 mm; Stroke, 250 mm; without Plate, cf. Fig. 52,921, p. 393 The pump exhausts to 0.0014 mm. 52.940. - - idem, with Plate 320 mm diameter ;md Barometer Gauge 300 mm high . . Largest Receiver for use with above: No. .->3,ll]6 £ 40. II. 0. til'. 66. o. s. tl. (t. 0 5. o 11. 6 1(1.0 5.0 15. o 11. is 117. 10.0 47.10.0 52. 941. - - i d e m, driven by a 1 H. P. 110 volt Direct Current Motor; on table with polished top and iron frame, without Plate, cf. Fig. 52;921, p. 393 52.942. - - idem, with 220 volt D. C. Motor 52.943. - - idem, with Plate 320 mm diameter and Barometer Gauge 300 mm high; with 110 volt D. C. Motor Largest Receiver for use with above: No. 5.'5,<»Ki 52.944. — idem, with 220 volt D. C. Motor 51. 0. 77. 78. 81. 0. i:.. o II. (i 10. (I 5. o 15. 0 11. r, S2. 10. 0 Rotary Oil Vacuum Pumps and Enclosed Vacuum Pumps. Rotary Oil Vacuum Pump, Fig. ."">!.', 946, with driving wheel, arranged for Hand and Cord Drive: suitable both for teaching and for Laboratories and Incandescent Lamp Factories; can be used specially as a prcliminarv pump for the Pointing Mercury Vacuum Pump. Sixe .' ' '....' 1 '2 :; I List Nd. 52,945 52.946 52,947 t Price t 7.0.0 8.0.0 10.0.0 For Hand and Cord Drive Water Air Pumps: see pp. 22 — 27. ci. Mia High Vacuum Pumps with Oil Packing, Kohl's System. Rotary Enclosed Vacuum Pumps. 395 52955. 1 : 15. 52962. 1 : 15. Size Power required at 160 — 130 r. p. m. V. . .approx. H. P. With 110 volt Direct Current Motor, on board with [ List No. 52,948 52,949 (hiving cord, switch, starter, connecting lead] 4 m long, plug and plug-box ( Price £ 15. 0. 0 16. 0. 0 With 220 volt Direct Current Motor, Accessories as ( List No. 52,951 52,952 above \ Price £ 15. 10. 0 16. 10. 0 3 Va 52,950 19. 0. 0 52,953 19. 10. 0 Rotary Enclosed Vacuum Pumps: can be used as Vacuum Pumps or Compressors, Figs. 52.955 and 52,962. Maximum r. p. m approx. 1500 1500 1000 800 800 .Max. quantity of air absorbed, approx. litres O \f\* per minute 145 320 520 1 (Kill 9fi7O Highest Vacuum, Mercury Co- AVW lumn mm 1.5 1.5 1 "> Power required approx. H. P. — — 0.9 3.0 -i- ,*j 4.5 AC n List No. — — 52,955 52,956 52,957 Xlo «. Vacuum Pump Price with Cooling Device and Oil Box £ 23. 15. 0 49 5 0 53 10 0 Packing £ 0. 10. 0 i«_/» t/« V 100 *J .ft -i-V/. \J 120 Weight | net ' ' ' aPProx' £g ( gross . . approx. kg 110 170 A» U« W 250 340 -*- • '»•* V/ 275 360 Max. Over-pressure approx. atm. 3 3 2.0 2.0 2.0 Power required at max. pressure approx. H. P. 0.95 1.9 2.0 7.0 10.5 As Compressor List No. Price with Cooling Device, with- 52,958 52,959 52,960 52,961 52,962 out Oil box £ 9. 10. 0 12. 0. 0 20. 0. 0 46. 10. 0 51. 0. 0 Packing £ 0.2.0 0. 2.0 0. 6. 0 0. 15. 0 0. 18. 0 W'Vlt ' ne* • • ' aPProx- kg 8,5 17 BO 175 200 [ gross . . approx. kg 14 25 85 250 270 These Rotary Pumps, Figs. 52,955 and 52,i)(>2, are specially suited for Laboratory use. They have no dead space and can thus produce high vacua — even to pressures of 1.5 mm mercury column: ihe Pumps can also be used as Compressors and employed thus they give 1.2 — 2 atm. over-pressure. When employing the Pumpfl as Com- pressors a correspondingly greater driving force is necessary if the Pumps are to be used to full advantage (see Table). The Vacuum Pumps are supplied with (Ml BOY. Fig. 52,9,V>; by placing the Pumps under oil they are cooled better and good packing and lubrication are obtained. Pumps Nos. 52,956, 52,957, 52,961 and n2,9<>;> have Water Cooling for the rotary part and the side part: in the case of Nos. 52,955 and 52,960 this Cooling is only extended to the lateral parts. The data regarding the quantity of air absorbed only apply when the air has a free passage and with maximum speed of Pump: witli lower speed the quantity of air absorbed decreases as the speed. Cl. 3660.5903. 396 Motion oi Gaseous Bodies. No. 52 52964. 1 : in. 52S83. 1:10. 52986. 1 : l.V 52987. 1 : 17. Rotary Vacuum Pumps (Enclosed Air Pumps) with Electric Motors, mounted on one baseplate. F i >j. r>L.'.iV.Hii. Revolutions per minute (Quantity of air absorbed, approx Highest Vacuum, Mercurx Column For 110 volts Direct Current approx. 1400 L350 1000 800 SOI) v. litres per minute 1 :?.-) 290 522 1(1(10 2670 Column . . . mm 2.6 L'.:» L.5 L.5 L.5 it I List No. 52,963 52,964 52,965 52,966 52,967 \ £ 23. 5. 0 27. 5. 0 49. 0. 0 85. 0. 0 97. 0. 0 Starter for above 1 0.8.0 0.8.0 1.2.0 2.6.0 4.2.0 if 1 List No. 52,968 52,969 52,970 52,971 52,972 It • • i 1 £ 23. 10. 0 27. 10. 0 49. 0. 0 85. 0. 0 97. 0. 0 Starter for above t 0.8.0 0.8.0 1.2.0 2.6.0 4.2.0 For 120 volts :5-phase Current For 210 volts .''.-phase Current approx. I Km 135 2.5 52,973 For 220 volts Direct Current With three-phase Motor. Revolutions pci minute . (,)iiaut it v of air absorbed. approx. litres per minute Highest Vacuum. Mercury Column . . . mm I List No. ' I I 20. 5. 0 Star-delta Switch or Starter for above t 1. 0. 6 I List No. 52,978 ' I t 20. 5. 0 Star-delta Switch or Starter for above t 1. 0. 6 Tin' D. C. Motors of No.,. .->:.'."(>.•!, .-,L'.!Mi». .VJ.'HiS. .-,L'.!Mi!> an- Scries Motors, the wound. The .'i-phase Motors of No-. .VJ.'.tTX .VJ.'.t" I. .V2.!I7S. .~>-.!l7!> ha\e -lion -circuited rolors. the remainder hiiviiiir rotor with slip-rim;-. The prices are understood to lie for the I'unip with Klectrie Motor t'ouplinj; ;urd Baseplate or r~|-I!ail- in the two larjrer rrrodcls. Please nole rcniiirks appended to No-, ."rj.'.'.'i'i ."i-J.'.HiJ. 1 Kill 300 2.5 52,974 24. 5. 0 1.0.6 52,979 24. 5. 0 1.0.6 940 192 L.5 52,975 49. 0. 0 1. 14. 0 52.980 49. 0. 0 1. 14. 0 690 L430 L.5 52,976 89. 0. 0 2. 11. 0 52,981 89. 0. 0 2. 11. 0 remainder 7011 2340 L.5 52,977 101. 0. 0 2. 11. 0 52.982 110. 0. 0 2. 11. 0 lieiii;; -hunt Rotary Enclosed Vacuum Pumps. Mercury Air Pumps. 397 52988. 1:15. 52989. 1 : 15. ">L',!)X3. Rotary High- Vacuum-Pump, Figure, Semi-Enclosed Vacuum Pump for belt or hand t s. d. drive; gives alone up to 0.05 mm mercury column (Ztschr. f. d. phys. u. elieni. 1". 19, I'.tOfi, p. 73) * 15.15.0 A higher vacuum than that mentioned above can be attained by using a separate preliminary pump. <'. g. a water air pump. For obtaining a vacuum of O.li(i:{ nun it is advisable to use a. second pump, built like the above, aa |ir«'liininary pump (see also No. .">:>. !)S.~>). The best speed is about 4nii i. p. m. when working without preliminary pump, and when working with preliminary pump about 2(10 r. p. in. ">2,!>X4. - - i d c in. with 110 volt Direct Current Motor, on one hoard, with starter . . . 30. 0. 0 The price varies if the motors a"e for a different current or voltage. In the ease of 3-phase or alternating current, kindly state frequency. >2.9X5. Two High Vacuum Pumps with 110 volt Direct Current Motor, on one board, one working as a preliminary pump; vacuum attainable, 0.003 rnm mercury column; quantity of air sucked up 70 and 35 litres per minute respectively 50. 0.0 Mercury Vacuum Pumps. 52. !»*«;. Mercury Vacuum Pump after Geissler, Figure, with polished oak stand; capacity of transport vessel, 1 — 1.5 litre The glass parts are the best product of the glass blower and are fitted with first rate cocks: the pump has three attachments for glass apparatus, massive and handy winding device; all metal parts excellently finished. Can. it desired, be provided with Supports, so as to be able to connect the air pump, by a length of tubing, with plates N'os. 50,139 — 50,142, p. 400. 10. 0. 0 52. !IS7. Mercury Vacuum Pump after Topler-Hagen-Neesen, Figure (M. P. I, Figs. 527 — 528 k[566 — 567]), with winding device, with all latest improvements ,988. Mercury Vacuum Pump after Sprengel, Figure, without cocks, on stand, holding 1 litre mercury (W. 1). Fig. 175 [160]) J,989. - - i d e m, after (iieiner and Friedrichs, Figure (Fr. phys. Techn. I, 2, Fig. 2614 [I, Fig. 323]) . . Cl. !»4li, 950. 9. 0.0 3. 15. 0 7. 10. 0 398 Motion of Gaseous Bodies. 52980. 1 : 15. 52991. 1:13. 52 992. 1 : 6. 52,990. Mercury Vacuum Pump after Spies, Figure (Ztschr. f. d. phys. u. chem. I". 8. £ s <'• 1894/95, p. 336) . 7. 0. () r>L'. '.»!»!. Automatic, Constant-action Mercury Vacuum Pump after Kahlbaum, Figure, for physical and chemical purposes; consisting of a Sprengel Mercury Air Pump combined with a Mercury Hoisting Apparatus (Wied. Ann. 53, p. 199, 1894; Ztschr. f. Instru- mentenkunde, 13, p. 73, 1893) 14.1(1.0 r>L', . (). 0 With the aid of this Pump, in conjunction with a. preliminary pump (the hitter must produce a vacuum of 15 — 10 mm) it is possible to obtain the highest vacua that can possibly be obtained with Mercury Vacuum Pumps, and this in the minimum of time. This Pump is therefore cminenth suitable both for the manufacture of glow lamps. Ilontjien tubes, etc. and For demonstrating in physical instruction, also for use in laboratories. As regards a Preliminary Pump it is advisable to use one of the Rotary oil Vacuum Pumps Nos. 62,901— 62,906, or aWaterAir Pump, A charge of about 1,6 litres i-O k^) mercury i> neces-ary and should if required be ordered separately. The Pump is of small and compact construction, is rapid in its action, and contains no vl:i-s. porcelain, or rubber parts. Tue rotating part and the carcase are of iron, bciui; thus unbreakable. The Pump is very smooth in its action. Kvery Pump is tested in our works for its efficiency by means of a Mac l.eod Vacuum Cau.nc and a certicate i;i\ iui: re.-nll of teM i> >npplied with the Pump. r.L'.IMt:!. - - The same Rotary .Mercury High-Vacuum Pump with ' ',„"' H. P. 110 volt Direct Current Motor, Figure, with starter, switch, connecting lead i m long, with plug box and plug, with Leather cord; the whole mounted on one board --. '». o Mercury Vacuum Pumps. 399 52 993. 1 : 8. > 53 001. 1 : 6. 52998. 1:15. 53000. 1:18. 52, '.tin. Rotary Mercury High Vacuum Pump as No. 52,992, with 220 volt Direct Current £ 8- d- Motor 22.10.0 ,~>o. I :>.">. Water Air Pump of glass, for preliminary exhausting, No. 50,135 0. 3. 6 51.292. Mercury, chemically pure 1 kg 0. 8. 0 52. !»97. Rotary Mercury Vacuum Pump, Kohl's System, with rotary Oil Vacuum Pump (as preliminary pump), both driven by one Motor for 110 volts Direct Current, mounted on j baseboard with starter, switch, connecting leads, plug and box plug !32. 10. 0 Illustration sent if desired. 52. 998 Mercury Distilling Apparatus after WeinhoM, Figure, for gas heating; supplies chemically pure, dry mercury and requires no attention (Carls Rep. 15, p. 1) ... The Apparatus consists of an oak stand, a Sprengel Mercury Vacuum Pump, the Distilling Appa- ratus with gauz- burner, a ga< pressure regulator, a heat regulator, the necessary bottles, etc.; it works quite automatically for hours and without any loss in mercury. Indispensable for those possessing Mercury Vacuum Pumps. 5u. !>!»((. - - i d e m, arranged for heating by Spirit Illustration sent on application. 8. 0.0 9. 0.0 2. 2. 0 r>:>.noo. -- idem, simpler, on wall board, Figure, with gas ring 5:5, ooi . Mercury Filtration Apparatus after Wiedemann, F i g u r e, consisting of a stand and funnel with long tube closed bv a piece of wash-leal her (\V. u. E. phys. I'rakt. Fig. 365; Ztschr. f. d. phys. u. chem. U. 4, 1891, p. 255) 0. 8. 0 5 1. :;(M. Mercury Press, see Figure 51,304, p. 215 0.12.0 Cl. 5097, 95fi, H.1-1, '.!'•'> 400 Motion of Gaseous Bodies. n. ;,:, 50 139. 1 : 5 50140. 1:5. 53 Oil. 1 : 9. 50 141. 1 : 6. 53017. l : -I Accessories for Vacuum Pumps. . Plate for Vacuum Pump, 24 cm diameter, Figure Without Receiver. Lar^eM Receiver that can in- used: No. .">:{. 013 4. <» :>n,i40. -- idem, with Barometer Gauge -Mio mm high; Finnic .......... i>. 14.0 ."id, I IL'. -- idem, larger, 2S cm diameter, with Barometer Gauge .'WU mm high, sled cock with brass handle ............................... 4. l.~». o I.aijicsl Receiver tliat can l>c used: No. .">;!. 111.") ...................... I'. t>. l> ), 141. -- idem, larger still, .'>-! cm diameter, F i <_MI re; \\ith Barometer Gauge .Him nun hijrli, with electric lead under the receiver, plii.ir terminals can be taken off plate; steel cock with brass handle ............................. 5. Largest Receiver iliai can In- n>cd: No. .•).'{.(> it; ............... . ....... ii. \Vhcn usinjc Receivers Nos. 53,008 — 53.O14 it is not possible to employ tlie lead terminals of this plate jis at least one terminal is COVITCI! over hy the receiver. c 1. -.'1,22, 5. 0 II. i> No. .'.3030. Accessories for Air Pumps. 401 53028. i : r>. 53029. 50,143. Rubber Tubing for Air Pumps, wire clad inside, braided; see No. 50,143, p. 25. per metre Price £ g. 0. 3. Receivers, F i g. 53,011, of good glass with wide flange and grip, finely ground. List No. 53,008 53,009 53,010 53,011 53,012 53,013 53,014 53,015 53,016 Internal Height mm 105 130 160 185 210 235 260 315 365 Internal Diam. mm 60 105 80 130 160 185 210 235 260 P?mp Plate°fmam } ^0 140 140 180 200 240 250 280 320 £ ls.9d. 2s.0d. 2s.3d. 3s.0d. 4s.0d. 4s.9d. 5s.6d. 6s.6d. lls.6d. The details given in the Table as to the diameter of air pump plates show the smallest glass plate which can be used with the receiver. For instance, Receiver No. 53,014 is suitable for a plate diameter of 250 mm; it is advisable, therefore to choose the smaller one, Nr. 53,013, if the larger is not absolutely necessary. In addition to the largest Receivers suitable for each plate it is desirable to select some smaller receivers for each air pump as the smaller the receiver the more favourable the action of the pump. The largest item given should be selected as well as Nos. 53,008, 53,010 and 53,012. We may say that the sizes of receivers suitable are appended to the description of the appa- ratus concerned. 5 3,01 7. Stuffing Box Receiver, Figure, 105 mm internal diameter, 150 mm internal height, for Bell No. 53,069 and Fan No. 53,066 0. 16. 0 The air pump plate for this receiver must be at least 140 mm diameter. 53.018. - - i d e m, 120 mm internal diameter, 160 mm internal height, for above experiments and for Electric Cascade No. 53,085 . 0. 18. 0 The air pumn plate must be 180 mm. 53.019. - - idem, 160 mm internal diameter, 210 mm internal height, for the largest air pumps having a plate of 200 mm diameter 1. 2. 0 This receiver is necessary for Bells Nos. 53,070 and 53,071 as well as for the double Pan No. 53,067. Rubber Discs of soft, red patent rubber for placing on the plate of the air pump so as to do away with the troublesome operation of smearing the receivers with tallow. List No. 53,020 53,021 53,022 53,023 53,024 53,025 53,026 Diameter mm 145 185 205 245 255 285 325 £ 0.4.0 0.6.0 0.7.0 0.9.0 0.10.0 0.14.0 0.18.0 53,028. Drying Apparatus for the air pump, Figure, with stopcock, mercury manometer attachment and 6 Tube Attachments The apparatus is arranged for drying by concentrated sulphuric acid. It is ground with great precision, being thus perfectly air-tight. 1. 0.0 53,029. Barometric Gauge, small, Figure 0. 8. 0 5.S.030. -- idem, larger, tube 200mm long, in glass bell with iron base 1.0.0 fl. 962, 595i. 402 Motion of Gaseous Bodies. 53 033. 1 : 5. 53034. 1:7 53031. 1 : 10. 53032. 1 : 14. 53035. 1 : 6. 53038. I : 4 53.031. Standing Barometer in receiver 85 cm high, with iron base, F i g u r e (\\ '. I). Fig. lf.7 * [153]), filled 1. 14. 0 53.032. Receiver with Barometer and Manometer, Figure, the barometer with charge . o. 12.0 Auxiliary Apparatus for Air Pumps. 53.033. Glass Sphere for weighing air, Figure, with two stopcocks, 120 mm diameter (W. D. Fig. 154 [168]) 0. Id. 0 53.034. Two Glass Spheres of 200 mm diameter, for determining the specific gravity of air, one of these being provided with foot for standing on the air pump, also with hook and tare pan, Pigu re (M. P. Ill, Fig. 91 [IT, 2, Fig. 85]) 1. 10. 0 53.035. Magdeburg Hemispheres, Figure, 100 mm diameter, of iron, with brass stopcock and ground base 0. 53.036. -- idem, 120 mm diameter 1. 53.037. - - i d e m, 200 mm diameter 1 . 53,038. Dasymeter (Baroscope), small, Figure (W. D. Fig. !<•!> [155]) Dasymeters Nos. 53.03s und 53,039 are for use with Receiver No. 53,012, and I>;i*vnietei- No. .Vi.o-lii with Receiver No. 53,015; for No. 53,038 No. 53,011 suffices, tmt the hirjrer receiver is pivtei ulile. 53,0311. - idem, larger, Figure 0. 53.040. -- idem, very large, for very large Air Pumps 1. 53.041. Dasymeter (Baroscope) after Prof. Friedr. ('. (i. Midler, Figu re, with pointer and scale, globe about 200 ecm (Miiller, Techn. d. phys. 1'iiteir., llioti. Fig. S7) .... 0. Smallest receiver that can be used: No. 53.011 0. 52,794. Demonstration Aneroid Barometer, see Fig. 52,794, p. 375 52,791. Bourdon Tube, si>e Fig. 52,791, p. 375, for explaining the principle of the Spring Mano- meter and of the Aneroid Barometer, on base, with scale and pointer 1. in. H o. o HI. 0 HI. 0 12. 0 H. H IS. 0 :j o Hi. (I Cl. SS.Vi. 117(1. !ii;i. .•.714. :!: No. 53 054 Accessories and Auxiliary Apparatus for Air Pumps. 403 53039. 1:4. 53041. 1 : 3. 53044. 1 : 6. 53 048. 1 : 5. 53052. 1:6. 53049. 1 : 6. 53050. 1 : 3. 53051. 1:2. 53053. 1 53.044. Apparatus for Bursting Bladders, Figure, 90 mm external diameter, of metal 53.045. -- idem, 150 mm external diameter, of metal 53.046. - - i d c in, 90 mm external diameter, of glass 53.047. - - i d e in, 140 mm external diameter, of glass Nos. .">:!, O44 and 53,046 can be used with small air pump; for Nos. 53,045 and 53,047 the diameter of tin; air pump plate, should be at least 180 mm. 53,04*. Apple Cutter, F i g u re, consisting of a receiver with fitting on top for holding an apple 53.ni!). Mercury Shower Apparatus, Figure, for showing the pressure of the air and the porosity of solids, with stopcock and foot, arranged for taking various fabrics . . . In tli is apparatus the forcing of mercury into the air pump is entirely obviated. 5:;, 050. -- idem, according to Figure 53,050, arranged for taking various materials 5.5. 051. Rubber Balloon, Figure, with stopcock, for showing the expansion of the en- closed aii- under the receiver (Gan.-Man. Fig. 130; M. T. p. 122) )3,05ii. Small Tripod with vessel underneath, Figure, for sucking a perforated egg by means of the air pump | 0 »3,o53. Apparatus for showing the uniform pressure of air in all directions, Figure . Large white metal pipe, cross shaped, with three openings, covered over with rubber. (3,054. - - id e in. with three brass hemispheres arranged above, sideways and underneath £ 0. s. d. 6. 0 0. 8. 0 0. 2. 0 0. 3. 0 0. 8. 0 0. 16. 0 0. 8. 0 0. 2. 0 0. 3. 0 0. 16. 0 1. Cl. 973, 4095, 987, 975, 3876, 3663, 986, 5326, 992. 4. 0 26* 404 Motion of Gaseous Bodies. No. 53055 — 53056. 1 : 3. 53055. 1:9. 53057. 1 : 3. 53 058. 1 : 6. fl 53 066. 1 53059. 1:8. 53060. 1 : 12. 53063. 1 : in. 53067. 1:4. 53.055. Syphon Fountain, Figure, svith stopcock and foot The apparatus after being exhausted is then . placed in a water vessel. After the stopcock is opened the water is driven in a jet into the tall glass tube by the action of the atmospheric air. 53.056. Small Heron's Ball, Figure, for placing under the receiver, with catching vessel 5 :;,057. Mercury Syphon, ceases to flow in vacno, Figure (W. D. Fig. 170 [156]) . . . Receiver No. 53,011 is necessary. 53,058. Air Reaction Wheel, Figure (Fr. phys. Techn. I, 2, Fig. 2689) llcreiver No. 53,011 is required. 53.05!t. Fall Cylinder after Weinhold, 0.6 m high, Figure (\V. I). Fig. 173 [158]), with long rod so as to enable it to be used as a stuffing box receiver The plate of air pump must be 180 mm in diameter. 53,060. Fall Tube (Newton's Tube), Figure, with stopcock and base, 70 cm high . . . ">3.061. Fall Tube with stopcock and base. 1 in high 53.062. - i d e m, 1.5 in high 0. 0. s. d. 0. 0 •2. 0 4. 0 0. 3. 0 1. 6. 0 I 1. '.I'.ll. '.!-<-. ill.'i. .Ml-JC 1I7II. !I77. !»7v 183, 1. 1. 1. . M4. 1'. 0 li. 0 IL'. 0 V... .',3076. Auxiliary Apparatus for Air Pumps. 405 53070. 1 : 3. 53072. 1 : 8. 53 071 and 53 019. 1:8. 53073. 1 : 8. 53074. 1 : 4. 53.063. Fall Tube after Puluj, Figure, evacuated and scaled up, 90 cm high, with base 1. An electromagnet is placed above the upper. end and when the current is closed this magnet holds fast a small iron disc and a down feather provided with a light iron wire. When the, current is opened both bodies drop simultaneously, reaching the bottom at the same time. 53.064. - - idem, not evacuated, for showing, along with No. 53,063, the behaviour of the two bodies in an air filled space 1. s. d. 10. 0 8. 0 53.065. - - i d e m, with stopcock, for evacuating on the spot, for showing the fall in air and in vacuo 1. 53,066. Wind Fan, for air resistance, F i g u r e (W. I). Fig. 174 [159]) . . . 0. 53,067. Double Fan, with two adjustable vanes, set into uniform rotation by two heavy racks, F i g \\ r e j 1. 52,667. Cohesion and Adhesion Tube after Leduc and Sacerdote, see No. 52,667, p. 361 . 0. 53,069. Bell with clockwork, for showing the small extent of the propagation of sound in rarified air 0. No. 53,069 can be used with the small Stuffing Box Receiver No. 53,017; the largest receiver, No. 53,019, is required for Nos. 53,070—53,071. >3,070. - - idem, hung with three cords in iron frame having rubber feet, Figure, for damping as far as possible the transmission of sound to the air pump 0. 14. 0 12. 0 15. 0 10. 0 12. 0 10. 0 i,071. -- idem, with visible clockwork, suspended by means of fibres, Figure, with- out receiver . 1. 53,072. Electric Bell in a receiver, suspended from rubber, Figure (M. T. p. 123) . 0. 0. 0 11'. 0 53.073. Apparatus for forming ice by evaporation of ether, F i g u r e, after Bottgor (W. V. Fig. 409), without receiver 0. 53.074. Freezing Apparatus after Cane, Figure (W. D. Fig. 391 [371]), for producing ice by evaporation, with enclosed ether vessel, on stand ' "• 53.075. -- idem, with stand, but without ether glass (W. D. Fig. 390 [370]) 0. 53.076. - - id e in, for placing direct on the air pump plate, F i g u r e (W. D. Fig. 392 [372]) 0. Ol. 980, 5991. !I82. 5312, 993, 994. 11. 0 9. 0 10. 0 406 Motion of Gaseous Bodies. No. 53077 — 53077. 1:7. 53078. 1 : 9. 60577. 1 : 7. 60 577 a. I : 8. 53082. 1:9. 53083. 1:8. 60578. 1 : 4. 53,077. Apparatus after Davy, Figure, for the reflection of heat in vacuo, receiver with two concave mirrors, heating wire and thermometer, for placing on the air pump (Gan.- Rein. Fig. 408) ............. ................... 3. 3. 0 53,078. Apparatus for demonstrating the cooling Action of Gases, Figure, after Tyndall (Tyndall, Warme, Fig. 83), with lateral hose stopcock for leading in gases and a stop- cook connecting with the air pump; for placing on the air pump plate ...... 60,577. Electric Egg, F i g. 60,577, with stopcock and base, for demonstrating Geissler Tubes (M. P., 9lh Edn., Ill, Fig. 240) ......................... 60,577 a. - - i (1 e m, Figure, with holders for taking carbon rods, for demonstrating t In- electric arc .................................. 60,577 b. - - i d e m, entirely of glass, without holders ................ 53.082. Receiver with Carbon Rods for producing an electric arc, Figure The air pump plate must be 240 mm diameter. 53.083. Glow Lamp Filament in Receiver, after Hartl, F i g u r e, for showing that the carbon filament docs not burn up in vacuo, but does so easily in air (Ztschr. f. d. phys. u. diem. T. 10, 1897, p. 235) .' ' <;<».. ">7S. Geissler Tube, with stopcock and base, for setting on the air pump, Figure. . r>.",.oxr>. Electric Cascade, consisting of Stuffing Box Receiver No. 53,018 and rranium Glass (\V. 1). p. X(>9 [807|) The air pump plate must be 180 mm diameter. 1'. (I. (I 1. 7.0 1. 10. 0 0. 18. 0 1. 12. (I 0. 15. (I (I. 16. 0 0. lit. 0 .-.::.:i lot. Auxiliary Apparatus for Air Pumps. Bellows. Compression Pump. Air Wheels. 407 53087. 1 : 5. 53089. 1:8. 53096. 1:8. 53099. 1:5. 53091. 1:7. 53101. 1 : 6. 53102. 1 : 6. £ s. d. 53.089. Model of Compression Pump, Figure, with rubber ball 0. 12. 0 53.090. Sectional Model of a Compression Pump (Kleiber, Oberstufe, Fig. 241) 1. 5. 0 53.091. Compression Pump after Silbermann (M. P. I, Fig. 553 [851]), Figure . . . . 4.16.0 The pump has a massive iron base, being provided with two valves and three stopcocks. It admits of compressing to 6 atm. 53.092. - - idem, with manometer 6. 0. 0 Gasometers and Aspirators, see under Nos. 51,244 — 51,277, pp. 211 — 213. 53.094. Compression Apparatus after Pouillet (M. P. I, Fig. 493 [534]), with compression screw and hand-wheel, for demonstrating the deviations from Boyle's Law 17. 0. 0 The apparatus has two tubes of 2 m length, also rule, and is tested at 130 atmospheres pressure. 53.095. - - i d e m, with bevel gearing 20. 0. 0 53.096. Air Reaction Wheel, Figure (W. D. Fig. 178 [163]), of glass, with brass holder and base, for blowing by the mouth 0. 6. 0 53.097. - - i d e m, entirely of metal 0. 8. 0 53,058. Air Reaction Wheel for the Air Pump, see Fig. 53,058, p. 404 0. 3. 0 ."•3.099. Gas Reaction Wheel, Figure, for driving with house gas or under the air pump receiver. When worked with gas the neck of the flask is half filled with water; the house gas flowing out is ignited (Fr. phys. Techn. I, 2, Fig. 3690) 0. 6. 0 52,593. Repulsion Apparatus after Hartl, see Fig. 52,593, p. 352 1. 4.0 53,101. Steam Reaction Wheel (Heron's Rotating Ball) of glass, in iron stand, Figure (Fr. phys. Techn. I, 2, Fig. 3691 [I, Fig. 641]) . . . 0. 5. 0 53.10:.'. -- idem, entirely of metal, Figure, with spirit cup 0. 14. o C'l. 3797, 5219, 5988, 5519, 997, 5872, 999. 408 Motion of Gaseous Bodies. 8 in:; 53108. 1 : (i. 53103. 1:11. 53105. 1 : 4. 53114. 1 : 4. 53115. 1 : 4 53.103. Draught Apparatus after Meidinger, Figure, comprising wide tube with burner and three lateral openings on to which lights are fixed It is possible to show with this apparatus the causes of draught, also the back draught in chimneys and the action of the wind on the draught in chimneys. 53.104. Sheet Iron Cone with lateral tube for showing the sucking action of chimney cowls (M. T. p. 128) ; . . . 53.105. Apparatus for Suction Phenomena of. Outflowing Gases, after Clement and Desormes, F i g u r e (M. P. I, Fig. 578 [596]) 53.106. Apparatus for Suction Phenomena (W. D. Fig. 179 [164]), with tapered blow pipe 53.107. -- idem, with constricted tube (W. IX Fig. 180 [165]) 53.108. Apparatus for Suction Phenomena, of glass, with brass mounts. Figure (M. 1'. I. Fig. 580 [508 1) 53.109. Model of Injector (Steam Jet Pump) after Keichert, F i g u r e, complete, with stand, boiling flask, spirit lamp, wood clamp and beaker 53.110. -- idem, without accessories named above (M. P. I, Fig. 581 [599]) Sectional Model of the Steam Injector: see Section "Heat". 53.111. Pulverising Tube of glass (M. P. I, Fig. 582 [600]) 53.112. Apparatus for demonstrating the Breathing of human beings. Figure, after Meut/uer (/tschr. f. d. phys. u. chem. I". 5, 1892, p. 305) .">.'», 113. - - id e m, with stand • 53,114. Sectional Model of a Clack Valve, of metal, Figure 5.",, 1 15. Sectional Model of a Ball Valve, of metal, Figure 53.116. Sectional Model of a Conical Valve, of metal, Figure 53. 11 7. Sectional Model of a Plate Valve, of metal. Figure £ 8. il. 0 IS. II 0. 3. (I 0. S. I) 0. 2. (t 0. 2. 0 0. 10. 0 o. 1 I. o 0. 3. (I o. o. 4 (I. 10. 0 (t. 11 0 0. 15. (I 0. 15. (I II 15. (I II. 15. 0 Water Air Pumps: *<•«• No*, .vi.127— .>o,K>f>. pp. -2-2— -2' i I. :>si;7. 3358, 1000. 3 3. V.I. 1008, HUM. linrj. No. .">:! I'.'S. Suction Phenomena, Valves, Wind Wheels, Screw Flyers. 409 53123. 1: 11. 53126. 1:7. 53.1 ix. Sectional Model of a Membrane Valve, of metal, Figure 53, 11 9. Sectional Model of a Safety Valve, with adjustable weight, of metal, Figure 53,120. Robinson's Cross Cups, Models (M. T., Fig. 91) 5.5.121. Windmill, of cardboard (M. T., Fig. 105) 53.122. Screw Flyer (Propeller) free-flying, Figure (W. D. Figs. 183 and 184 [168 and 169]), with throwing apparatus 53.123. - - i d e m, flying upwards on. a 1 m long wire, thus obviating any damage to objects. Figure 53.124. Throwing Apparatus wound by a spring, Figure, with one screw flyer . . . . By winding up the spring to a greater or less degree it is possible to rcgnlutc the height to which the flyer will ascend. The distance of ascent can be as much as 30 metres. 53.125. 10 Screw Flyers for above, as spares s. d. 15. 0 15. 0 6. 0 3. 0 0. 6. 0 16. 0 rj. o 53,126. Throwing Apparatus for Boomerangs, after Pfaundler, Figure, with 6 small alu- minium boomerangs of different shapes (M. P., 10th Edn. I, Fig. 327) 0. 2. 0 53,127. Boomerang (W. D. Fig. 185 [170]) 53,1 2X. Model of a Parachute (M. T. I, Figs. 588 and 589 [605 and 606]) Wind Vane and Wind Wheel for demonstrating the Propeller Fan: see No. 52,006. 1. 0. 0. X. 0 1. 0 8. 0 Water Air Pumps: sec Nos. 50, 127 — fiO,lor>, pp. 22 — 2~. Anemometers and Wind Vanes: sec Meteorology. Cl. 1009, 1003, 1004, lOOo, 1006, 1010, 1011,4942. 410 Molecular Effects of Gaseous Bodies. No. 53129 — a 53 131. 1 : 0. 53132. 1:3. 53 134. 1 : 5. 53 136. 1:3. 53 137. 1 : 4. Molecular Effects of Gaseous Bodies. 53.129. Dobereiner's Tinder Box, Figure 53.130. Air Gun, Figu re, ;i separate compression pump is not necessary 53.131. Brick with Fitting, Figure, for Pettenkofer's Experiment to show the Diffusion of Gases through porous walls (Kleiber, Oberstufe, Fig. 18; M. T. p. 129) 53.132. Apparatus for showing the Diffusion of Gases through porous Partition Walls (Trans- fusion), F i g u r e (M. P. Ill, Fig. 145 [I, Fig. 619]) 53.133. -- idem, with Manometer (M. T., Fig. 92) 53.134. Gas Endosmose Apparatus, after Weinhold, Figure (W. I). Fig. 188 [173]) . . 51,751. Double Sphere on Stand, for showing the expansion of gases (\V. D. Fig. 60 [55]) and The mixing (diffusion) of two -rases, after Berthollet (Gan.-Man., Fig. 163), see Fig. 51,751, p. 250 53.13<>. Demonstration Gas Indicator, Figure Mercury is introduced into the I"-tul)c until the lower current terminal is immersed therein. The upper contact is inserted a,s per illustration, the two terminal* arc then connected witli a cell and a bell, and house j^as is allowed to flow on to the diffusion partition. The fias diffuses in the funnel and forces the mercury out of the left limb of the tube until I lie circuit is finally closed. ."•:;. i:{7. Gas Indicator after Ansel], Figure, for showing the presenee of firedamp . . . .">3. 138. -- idem, as suggested liy Bunsen, Figure 53.139. Silver-Plated Copper Plate for Moser's breath figures (Fr. phys. Teolm. I. 2, p. 1031) 53.140. Endosmometer alter Meelai, Figure (.|. 1012, 5880, 1015,1016, £ 8. d. 0. 7. 0 1. 4. 0 0. 12. (i 0. 4. II 0. 4. II 0. »>. u 0. 10. 0 0. x. o 1. 2. 0 0. 12. 0 0. 5. li 1. 0. 0 5115, 5854, 1017. No. ~>3 14.'.. Molecular Effects of Gaseous Bodies. Wave Motions. 411 53 138. 1 : 8. 53 140. 1 : 9. 53 143. 1 : 10. 53 144. 1 : 10. V.i,l4l. Apparatus for showing the absorption of Gases through Solids and Liquids (M. P. II, Fig. 263 [I, Figs. 612 and 615]) VJ.I42. Absorptiometer after Bunsen, for the Absorption of Gases through Liquids (M. P. Ill, Fig. 265 [I, Fig. 616]) V5,143. Effusiometer after Henniger, Figure, for determining the velocity of outflow of (lases (Kohlrausch, Praktische Physik, 10th Edn., p. 91) £ s. d. 0. 2. 0 6. 0. 0 1. 6. 0 Wave Motions. >3,144. Longitudinal Wave Machine after Weinhold, Figure (W. D. Fig. 196 [181], | plate IV), for explaining the reflection of waves at the free and fixed end, as well as the existence of stationary waves, with copper spiral 170 cm long, fixed on rotary pegs d. 3. 12. 0 ,145. -- idem, each winding weighted with a lead ball I 4. 10. 0 Apparatus for showing the Elasticity of Air: see p. 366. CI. 1018,53.10. .v_>o:t. 1020. 412 Wave Motions. No. 53 I Hi 53146. 1:10. 53 148. ] : 14 f>3,146. Wave Machine after Much. F i g u re, for demonstrating progressive and stationary £ Longitudinal and Transverse Waves, also for converting transverse waves into longi- tudinal and vice versa ............................. .">. The Machine is provided with a driving arrangement l>y moans of which the different waves can ih be ]>ro.;.l47. Longitudinal and Transverse Wave Apparatus after van s< -haik (/tschr. f. d. phys. 11. cliein. 1T. 14, l!Mll. |i. X9; M. T. p. S(i), showing the longitudinal and transverse oscillations simultaneously ........................... X. (i. o r>.'{.lix. Wave Machine, Model for Hertzian Waves, alter Silvauus Thompson, Figure (S. P. Thompson-Lummer. Sichthares mid unsichtharcs Ijicht, 1X!)X, Fig. 1 .-»<); Slaliy. Die Fnnkenteleg7'a])hie, \>. 11, 19(11) ................. ..... . (i. 0. (> The radiator (primnrv station) forms a heavy mass of brass, suspended from fibres, and ha> a difinite period of oscillation, which is relatix'ely hi rye. The resomitor (secondary station) is a circle cut out of brass, this al>o beinj; suspended from fibres. No. 53 154. Wave Machines. 413 53149. 1 : 12. 53152. 1 : 17. 53153. 1:0. 5.3,149. Wave Machine after Hillig, Figure, with a .single and a double clamping board £ s. d. and with two adjustable bell cups fixed on stands 4. 0. 0 The apparatus represents an ether stratum and consists of a wood frame 1.5 x 0.5 m upon which a number of lead balls 1 cm in diameter are .strung, being connected with each other and with the frame by means of spiral springs. It is possible to demonstrate with this apparatus (1) the longitu- dinal wave; (2) the transverse wave; (3) the water wave (gravitation wave, in which the frame is placed horizontally); (4) the velocity of propagation (if the centre is plucked both bells ring simultaneously: equal velocity of propagation in the same medium); (5) polarisation; and (6) Huygens's Principle. A description is appended to each apparatus. * 53, 150. Apparatus for Demonstrating Wave Motions, after Grimsehl (Ztschr. f. d. phys. u. cliem. U. 19, 1906, p. 271), for demonstrating the Propagation, Eeflection, and Inter- ference of Water Waves #5:5,151. Lantern Slide for explaining Wave Motions Each 5:5,152. Wave Trough after VVeher, Figure, with glass walls 5:5, 153. Apparatus for the Repulsion and Interference of Wave Motion, F i g u r e (Fr. phys. Techn. I, 2, Figs. 3637 and 3639 [I, Figs. 565 and 566]), comprising an iron plate and dropping vessel for mercury on a movable stand, and two different elliptical vessels One vessel is filled with mercury until a smooth surface is formed. If now mercury is allowed to drop out of the dropping vessel in a focus of the ellipse, very visible waves are produced the repulsion and interference of which are rendered visible in a very pretty manner. The phenomena can also be projected by means of the mirror and lens No. 53.154. •53,154. Adjustable Mirror and Large Bi-convex Lens for above, to enable the phenomenon to be projected by means of the lantern 3. 15. 0 0. 1. 6 2. 4. 0 1. 4. 0 2. 5. 0 # Can be used with the Projection Apparatus. 5SOO, 338. 414 Wave Motions. Nc,. :,3155 — 53161. I:.", 53155. 53 162. 1 : 40. 53164. 1 : 12. 53 166. 1 : 9. 53,155. Rope Wave Apparatus after Volkinann, Figure (Fr. phys. Techn. I, 2, Figs. 3426, 3436, 3437; Ztschr. ,,Natur und Schnle", Vol. I, pp. 273—282 and pp. 342—350), for demonstrating the propagation, reflection, interference and polarisation of simple waves and trains of waves, the influence of the cord tension and of the cord weight on the wave-velocity, and of the compensation of waves of opposite phases 2. 5. o The apparatus consists of two end supports with hooks, 1 swinging lever for interference experi- ments. 2 polarisers, and 18 wire spirals. In addition, 3 to 4 stands are necessary for the experiments and are not included in the price: it is also advisable to provide stand clamps. 53,15*!. 4 Stands for Yolkmann's Eope Wave Apparatus J. I), it 53.157. 4 Stand Clamps for preceding Stands 1. o. o 53.158. Indiarubber Cords for transverse waves. 3 m long (\Y. 1). p. 244 |217'J) 0. 3. 0 5.").I.V.t. -- idem, weighted for half their length with wood balls 0. 12. 0 53,lfi(». Brass Wire Spiral on Silk Fibre, for reflection of transverse waxes (\V. I), p. 245 |218]) 0. 5. o 53. Hil. Brass Wire Spiral with Steel Rod for clamping, Figure (.M. T. pp. Sti and 87). for generating transverse and longitudinal waves 0. 2. 0 53.1<>2. Apparatus after Rosenberg, Figure, for demonstrating the propagation and inter- ference of oscillatory motions , 0. 12. 0 The apparatus consists of a long metal wire to which small wood pieces of square section are fixed at ecpial distances apart, these piece,s being of eqiuil length. OL 3363.4516. 1031, 1036, 1037. Nn. 53173. Wave Machines. 415 53 169. 1 53 172. 1 : 6. 53 173. 1 : 6. • £ s. d. 53.163. 2 Spiral Spring Models for imitating sound vibrations (M. T. Fig. 96) 0. 6. 0 53.164. Wave Apparatus after Melde; a gut string of 90 cm length which is set in synchronous vibrations by a tuning fork, Figure (M. P. I, Fig. 632 [659]) 2.10.0 53, 165. - - i d e in, with platinum wire string 0.35 mm thick, which is rendered incandescent by an electric current for making the experiment more apparent 4. 0. 0 53.166. - - i d e in, larger, with very massive fork and electromagnetic drive for permanently maintaining the vibrations, Figure, with gut string 5. 0. 0 53.167. -- idem, w-th platinum wire string 0.5 mm thick 7. 10. 0 53.168. Rotary Screw Spiral after Friedr. C. G. Miiller, for demonstrating progressive sine waves (M. T. p. 87) 0. 12. ,l 60. Transverse Wave Machine for the Projection Lantern, Figure (Fr. phys. Teclm. 1. L>, Fig. 3405) ' 2. 8. 0 53.170. - - i d c m, with 10 angle-shaped rods for demonstrating a longitudinal wave. . . 2. 1.2. o 53.171. NEW. Wave Machine after Steiudel, for transverse and longitudinal waves and for demonstrating the interference of two waves ! 6. 0. 0 Tin- Wave Machine comprises two machines of pattern No. 53,169, the excentrics of which -can be reciprocally adjusted so as to vary the phases of the two waves relatively to each other. The rods of the 1\vo machines are connected with each other by levers and set a third row of rods into motion, thus showing the interference of the two waves. 53.172. Transverse Wave Machine, Figure 53,1 73. Wave Machine after Fessel and Pliicker, Figure (M. P., 9th Edn., II, 1, Figs. 817 to 821), with two adjustable wave troughs and two sets of pins with balls on the ends for demonstrating transverse, circular and elliptic wave motion, of polished mahogany with iron legs 6. 0. 0 Cl. 5761,336-.', # Can be used with the Projection Apparatus. m-.':<. 416 Wave Motions. 53175. 1:7. 53 176 B. 1:12. 53 177 a. 1:7. 53,174. Wave Machine after Fessel and 1'liicker, F i g u r e, with a number of wave troughs; can he used .simultaneously for demonstrating double refraction 53,175. Wave Machine after Christian!, Figure (W. D. Fig. 190 [175]), for imitating aqueous waves. The mechanism is visible, being closed in by glass plate £ s. d. 16. 10. (I 5, (i. o 4. 0. 0 53,176. Wave Machine after Wheatstone (M. P. I, Figs. 607 and 608 [636 and 637J), with three different waves on one stand, 1 m long, Figs. A and B * 53, 177. Projection Wave Machine, cf. Fig. 53,1 77 a, with four round and two rectangular photographed discs; without box •_'. o. u The round discs demonstrate (1) the reflection of the elementary repulsion in a closed tulie; (2) the progressive longitudinal wave; (:i) the stationary longitudinal wave. i. e. the wave motion in an open tube, which gives its fundamental tone; and (4) the stationary wave in a tube dosed on one side. which gives the first o\er tone' (twelfth) of the fundamental tone. The rectangular discs arc used for demonstrating the reflection of a single wave at the closed and open end of a tnlic. *53,177a. -- idem, Figure, with 1>"\ for keeping the glass discs in * 53, 1 78. Wave Machine after ( 'ro va, Figure (M. I>. II, 1. Fig. 1. 0. (I (1) Stationary longitudinal wave. r.J) Progressive longitudinal wave. (.'!) Two longitudinal waves with phase displacement. Can lie used with the Projection Apparatus. 01. i "-'.•>. :>:>ti. 10:; l. HlL'ti-1. 111'.'!!'-. 5041, V No. ,3 Wave Machines. 417 53 178. 1 : 6. 53179. 1:11. 53 180. 1 : 7. 53.179. Stroboscopic Cylinder, on stand, Figure, with 18 wave strips, after Quincke £ s. d. (M. P. II, 1, Fig. 295 [394]) 0. 18. 0 For demonstrating pendulum oscillation, longitudinal and transverse oscillations, vibrations of ether particles, reflection of cord waves, vibration of strings and of air strata in pipes, vibration of liquid particles and of progressive transverse waves. 52.019. - - idem, fitting the Whirling Table, with 18 wave strips, after Quincke .... 0. 14. 0 52.020. Strips alone, 18 in number, in case, with description 0. 6. 0 53.180. Wave Apparatus for Explaining the Vibration of Sounds, Figure (W. D. Fig. 255 [241]) 2. 10. 0 53.181. Wave Machine after Pfaundler (M. P., 10th Edn., I, Figs. 624 a— e and 803; Ztschr. f. d. phys. u. chem. U. 1, 1888, p. 98), for deriving combined transverse waves, especially for the compounding of the wave of a fundamental tone with the waves of the uneven overtones 5. 10. 0 53.182. Wave Machine after Grimsehl, for the synthesis of vibrations, with the rod for the sine shaped wave of a fundamental tone and for two ovei tones (Ztschr. f. d. phys. u. chem. U. 17, 1904, p. 34; Physikal. Ztschr. 1904) 8. 15. 0 Cl. 336, 1033, 1036. 27 418 Acoustics. No. 53183 — 53 183. 1 : 4. 53 187. 1 = 5 53 189. 1 : 53 184. 1 : 9. 53 185. 1 : 6. 53 186. 1 : 4. 53 191. 1 : 4. Acoustics. Propagation of Sound, Pressure Changes, Reflection, and Refraction of Sound. Bell with Clockwork for proving that air carries the sound waves, for placing under air pump receivers, see Nos. 53,069 — 53,071 on p. 405, also electric bell in receiver, No. 53,072. 53,183. 2 String Telephones, Figure (W. D. Fig. 204 [190]) 53.184. Apparatus for demonstrating the Propagation of Sound in Liquids and Solids, F i g u r <• (Tyndall, Sound [der Schall], Fig. 28), comprising resonance box with attachments and tuning fork The tuning fork is struck or bowed after being, together with its small wood base, screwed off the sound box, the sound, however, being scarcely audible. If it is now placed upon the box or on one of the wood or brass rods screwed to the box, the sound is considerably intensified. This intensifi- cation of sound also takes place when the tuning fork (together with wood base) is placed in the funnel of the glass tube, filled with water, and screwed on to the sound box, even though the wood base of the fork be not in contact with the wall of the funnel. 53.185. Sensitive Flame Burner, after Konig, Figure, working with certainty with the usual gas pressure of 35 mm 53,186. - - idem, after Weinhold, simpler, Figure, with wire net, without sound horn 53,187. — idem, after Weinhold (W. D. Fig. 198 [183]), Figure . For rubber bags for the latter apparatus, see Nos. 51,267 — 51,270, p. 21-2. £ s. d. 0. 8.0 1. 10. (I 1. 0.0 0. 8.0 0. 6.0 Cl. 5857. 1018, 1040,5788, 1038, 1039, 1759. No. 53 197. Propagation, Velocity, Pressure-Variation, Reflection, Refraction of Sound. 419 53 193. 1 : 2. 53 197. 1 : 8. 53 194. 1 : 24. 53 196. 1 : 25. 53.188. Sensitive Flame, after Rebenstorff, generating its own gas (Ztschr. f. d. phys. u. chem. U. 19, 1906, p. 281) The apparatus is fed with a mixture of equal parts of ether and benzol; the gas issuing from the burner nozzle becomes mixed with air and is ignited above the net. The sensitivity can be altered by regulating the air current by means of the rubber bellows. The differences in sensitivity on pro- nouncing different vowels can be shown. 53.189. Air Concussion Apparatus (Fr. phys. Techn. I, 2, Pig. 3708 [I, Fig. 668]), Figure, funnel-shaped with drum-stick 53.190. - - idem, after Weinhold (W. D. Fig. 199 [184]), cylindrical, with drum-stick . 53.191. Kundt's Manometer with stopcocks, after Trussevitch, Figure, with funnel and indicator for the air currents, on stand (Fr. phys. Techn. I, 2, Figs. 3711 and 3735) The flap valve, formed of a fish-bladder membrane, is placed inside a tight-fitting conical stop- cock. By turning the stopcock through about 180° the valve can be used as a pressure or suction valve. The pointer shows the direction in which the flap opens. The apparatus should be connected, by means of a length of rubber tubing to be attached, with a suitable manometer, e. g., Kolbe's Thermo- scope. The apparatus is peculiarly adapted for Rostovzev's experiment on the reflection of sound waves (Ztschr. f. d. phys. u. chem. U. 16, 1903, p. 288), in conjunction with two concave mirrors and the pipe No. 53,192. 53.192. Tuned Pipe for above, on stand, Figure (Fr. phys. Techn. I, 2, Figs. 3726 and 3735) 53.193. Apparatus for showing the Pressure Change in Sound Waves, after Szymanski, Figure (Ztschr. f. d. phys. u. chem. U. 1, p. 148; W. D. Fig. 201 [186]) . . . . 52,730. Pressure Level, after Topler, Figure 52,730, p. 368 (W. D. Fig. 141 [187]) . . 53.194. Tyndall's Apparatus for showing the Propagation of Sound in Long Tubes, Figure (Tyndall, Sound [der Schall], Fig. 4; Fr. phys. Techn. I, 2, Fig. 3709 [I, Fig. 669]), with telescopic sheet iron tube 3 m long, with supports 53.195. Drawn Brass Tube, after Eebenstorff, for demonstrating the conservation of the density of sound without lateral propagation (Ztschr. f. d. phys. u. chem. U. 19, 1906, p. 279), as well as for thermal expansion in large dimensions (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 248); total length 4 m; width 20 mm; in two parts, for heating by steam 0. 10. 0 3,196. Megaphone, Figure, 2m long, carrying distance 1000 m (W. D. Fig. 202 [188]) 3 196 a smaller of lacquered sheet iron 0. 10. 0 0. 6.0 3,197. Sondhaus's Lens, Figure, for demonstrating the refraction of sound, on stand, 300 mm diameter (Fr phys Techn I, 2, Fig. 3736) 1. 13. 0 Two rubber membranes stretched on a round metal frame can be filled with carbonic acid and a bi-convex lens blown. Tone Manometers after Grimsehl: see No. 53,275, p. 429. ci.neo, 1012,10 Sound Manometers after Dvorak: see later on in list. 50, 27* s. d. 18.0 10.0 9.0 1. 0.0 0. 12. 0 0. 0. 9.0 5.0 1. 4.0 420 Acoustics. No. 53199 — 53 201. 1 : 7. 53 204. 1 : 3. 53 208. 1 : 3. Sound Generation, Sirens and Blowers. £ s. d. 62,315. Apparatus after Wertheim, Figure 62,315, p. 957, for demonstrating the tones of steel when magnetized (M. P., 9th Edn., Ill, Fig. 530) i 2. 10. 0 53.199. Trevelyan's Rocker, Figure (W. D. Fig. 206 [192]), with resonance box, for pro- ducing tones by a succession of concussions 0. 15. 0 53.200. - - idem, without resonance box 0. 12. 0 53.201. - - idem, after Konig, Figure 0. 14. 0 52.028. Savart's Toothed Wheels, see Fig. 52,028, p. 283; 4 wheels, giving the common chord, suitable for Whirling Table, of zinc 0. 9. 0 52.029. --idem, of brass 0. 12. 0 52,021. Siren Disc, F i g. 52,021, p. 283 (Seebeck's Siren), with four rows of holes, giving the major chord, for placing on the whirling table 0. 5. 0 53,203 a. Siren Disc, with 8 rows of holes, giving the scale, for the Whirling Table ... 0. 7. 0 53,203 b. - - idem, with 8 rows of holes, giving major and minor chords 0. 7. 0 53,204. Pipe with 4 nozzles, Figure, for blowing the preceding Siren Discs 0. 5. 0 52.026. Siren Disc after Oppelt, with 22 rows of holes, for placing on the Whirling Table 0. 16. 0 The disc has 22 rows of holes; 15 give simple tones, 7 give different intervals as combined tones. 52.027. Siren Disc after Appunn, for placing on the Whirling Table, with 32 rows of holes; gives the simple chromatic scale, the passage of thirds, also the entire song, ,,Du Schwert an meiner Linken" in the four parts 3. 6. 0 52.024. Wave Siren Disc after Konig, for placing on the Whirling Table, with 2 tubes for blowing the rows of holes and the wave line 0. 15. o The Wave Siren Disc has 4 rows of holes having respectively 32, 40, 48 and 64 holes and a wave line on the edge corresponding to the algebraic addition of 4 sine curves corresponding with the above numbers of vibrations. When the wave line is blown upon, the result is a sound which is broken up by the ear into its single constituents, prima, third, fifth and octave. The disc is excellently adapted for explaining the sound action of the phonograph and gramaphone. 52.025. - - idem, after Konig, larger, shaped to correspond to the flame image of the tone. Is supplied hi the intervals 8:9, 8 : 11, 8 : 12, 8 : 13, 8 : 15, 8 : 16, 8 : 18, 8 : 20, 8 : 23, 8 : 24 Price each 3. 6. 0 53.208. Universal Mouthpiece for blowing the cavum oris, flasks etc.; comprising rubber tubing with flat tapering brass tube (W. D. p. 312). with conical endpiece for inserting in a valve aperture of the blowing table 0. 7. <) 53.209. Siren after Cagniard de Latour, Figure, small pattern, with row of 12 holes, with- out counting mechanism (Helmholtz, Tonempfindungen, 4th Kdn., 1877, p. 22), with conical tube for placing on the wind chest. All holes are blown through simultaneously, thus adding to the intensity of the effect 1 . 10. 0 53,2.10. — i d e in, with counting mechanism, Figure (M. P. I, Figs. 673 — 675 [699—701]) 2. 0. (• 53.211. -- idem, larger pattern, with series of 20 holes, without counting meetianism, Figure, with conical tube attachment for placing on the wind chest and with wood base for protecting 53.212. - - idem, with counting mechanism 4. 10. 0 ' i :isoi, 1051. 1054, 4146. No. 53214. Generation of Sound, Sirens, Blowers. 421 53 209. 1 : 4. 53 210. 1 : 4. 53 211. 1 : 4. 53 213 A. 1:4. 53 213 B. 1:3. 53 214. 1 : 6. 53,213. Chord Siren aftei Dove, Figs. A and B, with 4 stops with stop catches, to enable the tones to be sounded singly or together, and with counting mechanism (Helmholtz, Tonempfindungen, 4th Edn., 1877, p. 23; M. P. I, Figs. 839, 840 [814, 815]) .... 53,214. Siren arranged to sound under water, Figure, with glass vessel This Siren, built on the principle of Cagniard de Latour, is placed in the glass vessel supplied and connected by a length of tubing either with the water lead or with a tank placed on a higher level. If the stopcock is opened the water flows through the siren and the latter sounds. 6. 14. 0 6. 0.0 Cl. 3669. 3669», 3669 b. 3669 c, 3669 e, 36711. 422 Acoustics. No. 53215 — 53 215. 1 : 6. 53 216. 1 : 8. 53 219. 1 : 6. 53,215. Double Siren after Helmholtz, for working by means of compressed air, Figure, with counting mechanism which closes an electric contact when set into action (Helm- holtz, Tonempfindungen, Fig. 56, pp. 268, 291, 303, 652; M. P. I, Fig. 816 [841]; W. D. pp. 260 and 330) The Double Siren is very suitable for a large number of important experiments in acoustics and the theory of music, being particularly adapted for these purposes since tin- ratio of the frequencies of the single tones always remains unaltered. The following intervals of tone can lie produced: unison, octaves, fifths, fourths, major third, minor third, whole tone and semi-tone. Special mention may be made of the experiments on the interference of sound, on vibration, on deep and deepest tones, on vibrations of the overtones, and on combined tones. The perforations of the one disc correspond to the tone ratios c : e : g : d,, the perforations of the other correspond to d : g : b : ct. The upper wind chest can be turned by a handle for the purpose of obtaining in the upper siren any phase difference as against the lower one. Cl. 1059, 1060, 1055. £ s. d. 16. 0. 0 No. 53220. Double Sirens, Wave Sirens, Siren with Blowing Table. 423 53 220. 1 : 13. 53.216. Double Siren after Hebnholtz, driven by a 110 volt D. C. electric motor, Figure, with counting mechanism which when inserted closes an electric contact The electric motor has a regulating resistance and a controllable brake device so as to be able to adjust the siren to any pitch with certainty. The apparatus is very simple to manipulate. The siren is driven by a thin belt, the motor being adjustable so as to keep the belt always taut. In other respects the siren is similar to No. 53,215. If a different kind of current or voltage is desired the price is proportionately altered. When ordering kindly state kind of current and voltage for the motor; in the case of alternating and three- phase current the frequency should also be given. 53.217. Electric Motor alone, with board, adjusting arrangement and regulating resistance Cf. the remarks mentioned under the preceding item. 53.218. Model of the Ship's Siren with concentric, pierced cylinder jackets, the innermost being rotary (Bolte, Leitfaden f. d. Unterr. i. d. Physik an Navigationsschulen, 2nd Edn., Fig. 108) ; the essential parts, visible through glass, should be placed on the wind chest 53.219. Large Wave Siren, after Konig, Figure, for investigating sound impulses with wind chest and siren disc the rows of holes of which correspond to the periodicities of the primary tone and the repelled tones The apparatus is for showing impulses and impulse -tones produced by the tones of different intervals; the impulses are attained when the rotation is slow and the impulse-tones when the rotation is rapid. A siren disc with holes is used for comparison with the tones produced by the wave siren. The curves, which are arranged cylindrically, result from the combination of the two sine curves pertaining to the interval. When a blast is applied a motion of the air results corresponding to that produced by the consonance of two actually simple tones, without any intermingling of overtones. Given in with the apparatus are the waves for the eight intervals 8 : 9 to 8 : 16, and an arrangement is fitted to allow the sirens to sound separately and together. The sirens are actuated by a cord pulley. 53.220. Blowing Table with Siren, Figure, for demonstration purposes (Model of the German Museum, Munich), siren with Electric Motor Drive; the four rows of holes give the major chord and can be blown either singly or together by using a keyboard. The motor has a regulating resistance so as to be able to raise the fundamental tone an octave, from 256 vibrations to 512 vibrations Unless otherwise stated when ordering, we supply the motor for 110 volts Direct Current. Cl. 4921. »• d 26. 10. 0 10. 10. 0 2. 10. 0 45. 0. 0 22. 10. 0 424 Acoustics. No. 53221 — 53226. 1:12. 53 229, 53 492, 53 493, 53 494. 1 : 14. Cl. 1061. 5980, 5108,3370. No. 53232. Blowing Tables and Bellows. 425 53 232. 1 : 15. 53.221. Blowing Table for Acoustic Experiments, Figure, with two large and four small £ s. d. tube attachments with valves | 7. 0. 0 The Blowing Table has a large valve for receiving large reed pipes, a tube attachment with plug seal for the overtone apparatus or a special wind chest; four valves for sirens and pipes, and two tube unions of different sizes with plugs, for various purposes. The table frame is constructed of pine, the top of oak. 53.222. - - idem, with eight valves, otherwise as No. 53,221 8. 0. 0 53.223. - - idem, with thirteen valves, otherwise as No. 53.221 9. 0. 0 53.224. Blowing Table with Wind Chest and Keyboard, Figure, for all acoustic experiments; with a large valve for a large reed pipe or a tonometer; with eight small valves and two different pipe attachments for rubber tube connections. The valves are opened by a keyboard which can be regulated and fixed in place. Size of bellows 37 X 57 cm |15. 0. 0 63.225. - - idem, with twelve valves 18. 0. 0 53.226. Blowing Table with Electric Motor Drive, Figure, with 110 volt D. C. Motor, with fuse, switch and starting resistance, in lock-up cabinet with doors 24. 0. 0 With two large conical pipe attachments with plug seals, for taking tonometers and overtone apparatus; a large valve for large reed pipe; four valves for sirens and pipes and two hose unions of different sizes with plug seals, for various purposes. The table frame is of pine, the top of oak. 53.227. - - idem, with eight valves 25. 0. 0 53.228. - - idem, with thirteen valves 26. • 0. 0 53.229. Blowing Table for Constant Pressure, Figure, specially adapted for use in ex- periments with tone variators Nos. 53,481 et seq., for continuous experiments with Galton's whistle, Quincke's tubes, etc. Price without tone variators 9. 0. 0 53.230. Double Blower, after Whipple, for constant pressure, Figure, with two wind chambers arranged as gasometers. The chambers are employed alternately, the transfer being made quite easily {22. 0. 0 The blower gives a very uniform wind both when the chamber is filled and empty. The in- fluence of the alteration in water level on the height of pressure is compensated by efficient arrange- ments. The pressure can be regulated. A Stern Tone Variator can be supplied with air for about 25/2 minutes without interruption. r>.'),231. Wind Chest on Table, with four small and three large valves, cf. F i g. 53,506, for use with the Whipple Double Blower No. 53,230 | 7. 10. 0 53,232. Acoustic Bellows, Figure, with four valves and a pipe attachment for taking reed pipes j 4. 10. 0 01. 3371, 5995. 426 Acoustics. No. 53233 — 53 234. 1 : 9. 53 233. 1 : 10 53242. 1:8. 53 235. 1 : 5. 53 238. 1 : 7. 53238a. 1:4. 53.233. Acoustic Bellows after Bertram, Figure, hand driven, with four valves and a £ * ''• tube attachment for taking reed pipes 3.0.0 53.234. Wind Pressure Regulator for Sirens, Figure 1. 16. 0 The apparatus is employed for lessening the impulses which cannot to be entirely avoided when foot bellows are used. 53.235. Wind Chest, Figure, with four valves, for placing on the blowing table having no valves or for use in conjunction with the water jet blower l. r_'. o The Wind Chest can also be worked with compressed air from steel bombs. In this case the following are necessary: 1 Steel Bomb No. 50,947 (£ 1. 16. 0), 1 pressure reducing valve No. 50,953 (£ 2. 5. 0). The cost of charging the bomb (No. 50,947) is £ 0. 10. 0. 53.236. - - idem, with eight valves 2. 10. 0 53.237. - - idem, with thirteen valves 4. 0. 0 Vibrating Air Columns, Pipes, Sound Analysis. 53.238. 4 Tubes with pistons, Figure, giving a chord when the pistons are successively drawn out 1. 16. 0 53,238 a. 3 Covered Pipes, Figure, of metal, with wood mouthpiece, for the tones c8= 1024, C4= 2048 and c5= 4096 vibrations (uts= 2048 v. s., ut6= 4096 v. s., ut7= 8192 v. s.) 0. 18. 0 53.239. Labial Pipe of wood, to be used open and closed 0. 10. 0 53.240. — of tin, cf. Fig. 53,245 0. 8. 0 53.241. - - of wood, with middle slide, giving the same tone open and closed 0. 16. 0 Cl. 5992, 5996, 1083, 1066, 4099, 5054. No. 53259. Vibrating Air Columns, Pipes. 427 53 245. 1 : 8. 53 251. 1 : 3. 53 253. 1 : 3. 53254. 1: 25. tones £ s. d. 53.242. Labial Pipe of wood, Figure, for opening out to explain the internal arrangement 0. 10. 0 53.243. Labial Pipe, with side holes which can be closed and with adjustable wind orifice 0. 12. 0 53.244. 2 Long Brass Pipes, one open, the other covered, for giving the succession of harmonic 0. 16. 0 53.245. 4 Labial Pipes of Zinc, Figure, major chord c1? elt g1; c2 (ut3, mia, so!3, ut4) . 1. 4. 0 53.246. 4 Labial Pipes of wood, for the major chord ct, e1? g1; c2 (ut3, mi3, so!3, ut4), each pipe with slide for accurately tuning 53.247. 8 Labial Pipes, Figure, for the diatonic scale Cj— c2 (uts — ut4) 53.248. - - idem, larger, from c0 — Cj (ut2 — ut3) 53.249. 13 Labial Pipes for the chromatic scale ct — c2 (ut3 — ut4) 1. 12. 0 2. 16. 0 4. 0.0 4. 10. 0 53.250. — i d e m, larger, from c0 — cl (ut2 — ut3), each pipe with slide 6. 0. 0 53.251. Organ Pipe Mouthpiece, Figure, with adjustable upper lip 53.252. Cornet Mouthpiece, Figure 53.253. Clarinet Mouthpiece, Figure 53.254. Large Double Pipe with adjustable tone, Figure, 2m long, 10 cm square, with one mouthpiece, with two slides and two adjustable pistons 53.255. 2 Open Pipes, of the same tone, one of which can be tuned by a slide for producing impulses 53.256. Labial Pipe, with parchment wall, open, for putting out of tune by damping . . 53.257. Labial Pipe, Figure, with adjustable, graduated piston, for producing the tones of the scale Cj — c2 (ut3 — ut4) 53.258. Small Double Pipe, with two sliding pistons, for the chromatic scale from c2 — c3 (ut4 — ut5), forblowing with the mouth 53,259. Horn without reed, after Dvorak, for the tone cx (ut3) 0. 8.0 0. 4.0 0. 4.0 3. 4.0 1. 2.0 0. 12. 0 0. 16. 0 0. 16. 0 0. 3.0 For Wind Chests for Pipes: see Nos. 53,235—53,237. Blowing Tables and Blowers: see Nos. 53,221—53,233. Cl. 5975, 4182, 1087, 4149, 4159, 1086, 1084. 428 Acoustics. No. 53260 — 53260. 1 : 9. 53261. 1 : 10. 53263. 1:11. 53262. 1:10. 53 265. 1 : 8. 53266. 1 : 13. A B 53 267. 1 : 8. 53.260. Labial Pipe with adjustable membrane, for showing the vibratory nodes, Figure, £ s- d. of wood, with glass wall 0. 16. 0 53.261. Labial Pipe with adjustable membrane, Figure (M. P. I, Fig. 653 [687]), for showing the vibratory nodes, with long glass tube 1. 0. 0 53.262. Labial Pipe with long glass tube and sliding piston, Figure 1. 4. 0 When the piston is in a vibratory node, the fundamental tone of the pipe is maintained, while in the other case it is altered. * 53,263. Manometric Flame Pipe, after Konig, Figure, with three gas flame manometers, for demonstrating the nodal points, with glass wall and brass fittings, also with sheet iron inset so as to be able to project the phenomenon in reflected light by means of soap bubbles (W. D. Fig. 209 A [195 A]) 1.16.0 The pipe is placed on the small table supplied with our Projection Lanterns. The objective, however, must be set up, at right angles to its usual position, alongside the projection lantern, at a corresponding height, e. g. on one of the small tables Nos. 51,133 — 4, 51,136 — 7, or 51,139 — 40. Tilt- projection lantern itself is set up parallel to the screen. The optical bench is then unscrewed, tin- lantern alone rotated, and the pipe, with the objective, placed on the optical bench (cf. W. I). Fig. 210 [196]). 53.264. -- idem, with Topler's Flame Indicators (W. D. Fig. 209 B [195 B]) L. 12. fl 53.265. Kundt's Covered Pipe, Figure, with 3 Water manometers and valves seals . . 2. s. o 53.266. Labial Pipe, Figure, in the nodes of which holes of different diameter can be opened 0. 16. 0 53.267. 2 similar Labial Pipes, Figs. A & B, with mouthpieces in different directions, for showing that the position of the mouthpiece is without influence on the tone ... 1. -4.0 53.268. 2 Labial Pipes, Figure, the open ones giving the tones, 1, 2, 3, 4, the closed ones the tones 1, 3, 5, 7; with directions for use 1. TJ. n 53.269. Open Pipe, of boxwood (Fr. phys. Techn., 6lh Edn., II, Fig. 977), for showing tlmt higher tones can be produced in a narrow pipe by intensified blowing; without wind chamber 0. S. 0 53.270. Cubic Pipe with adjustable wall, Figure 0.16.0 53.271. Cubic Labial Pipe, open 0. 12. o 53.272. 2 Closed Cubic Pipes, of different size, Figs. A and B, for demonstrating I lit- influence of the volume of air on the tone 0. 16. 0 53.273. 2 Covered Triangular Prismatic Labial Pipes, for the same law 0. 16. 0 Cl. 5982, * Can be used with the Projection Apparatus. 4978, 1089, 1000, 5989, 5976, 5077. No. 53285. Labial Pipes, Reed Pipes. 429 53 270. 1 : 5. 53268. 1:10. 53 272 A. 1:10. 53 272 B. 1:10. 53278. 1:10. 53 282. 1 : 10. 53284. 1 : 10. 53.274. 3 Open Labial Pipes, of same length and same air capacity, but of different tone; £ »• d. for explaining that the tone is also dependent on the shape of the pipe; one in the form of a truncated pyramid, the second of rectangular prismatic form, the third in the form of a pyramid trunk widening out upwards 1. 13. 0 53.275. Tone Manometer, after Grimsehl (Ztschr. f. d. phys. u. chem. U. 2, 1888 — 89, p. 59), a U-shaped water manometer with valves for hanging in pipes 0. 6. 0 53.276. Small Disc with rotary suspension, for showing the motion of air in singing air-columns, after Grimsehl (Ztschr. f. d. phys. u. chem. U. 2, 1888 — 89, p. 59); it is placed, hori- zontally, hung in the vibrating centre of a pipe I 0. 4. 0 53.277. Steam Pipe (Bolte, Leitf. d. Phys., 2nd Edn., Pig. 109), for placing on the wind chest 1. 10. 0 53.278. Reed Pipe, Figure, with freely vibrating reed, tone varied by making the reed longer or shorter; with two resonators 0.18.0 53.279. - - idem, with restricted-motion reed 0. 18. 0 53.280. Free-vibrating Reed Pipe, after Weber 3. 0. 0 This pipe is arranged in such manner as to render it possible to use reeds constructed of sheets of different thickness and material. The pipe rests in a glazed wind chest and carries its pipe, which can be interchanged by a whole series of others of different length; such a pipe is formed of two pipes sliding one in the other. If the tone of the pipe harmonises with that of the tube, and if the pipe is gradually lengthened, the tone is not lowered proportionally to this lengthening. The lowering takes place slowly at first and then more rapidly until the lower octave exactly is reached when the tube is drawn out double length. If now the tube be again increased by its own length the tone goes back first to the initial pitch attained, being finally lowered as in the preceding case — '- only, of course, by an interval of a fourth. 53.281. Membrane Reed Pipe (M. P. I, Fig. 777 and 778 [801 and 802]) 0. 5. 0 53.282. Reed Pipe with Sound Trumpet, Figure, c_x = 64 vibrations (utx= 128 v.s.), powerful tone 1. 6.0 53.283. - - i d e m, c0 = 128 vibrations (uta = 256 v. s.) 1.6.0 53.284. Horn with Reed, c: (ut3), Figure, after Dvorak, for experiments on the mechanical effects of sound (Ztschr. f. d. phys. u. chem. U. 6, 1893, p. 186) | 0. 4. 0 53.285. Foghorn, model for placing on the wind chest (Bolte, Leitfaden d. Phys., 2nd Edn., Fig. 109) 2. 5. 0 Cl. 1097, 5979, 1098. 1099, 1103, 1106, 3384. 430 Acoustics. No. 53286 — 53 294 B. 1:1. 53289. 1:11. 53 287. 1 : 10. 53 290. 1 : 20. 53291. 1:8. 53 294 A. 1:8. 52.286. Chemical Harmonica (Apparatus for singing Flames), cf. Fig. 63,287 (W. D. Fig. 211 [197]), comprising 4 tubes tuned to give a chord, each provided with stopcock and with cap for covering the tubes so that each tone can be sounded singly 53.287. - - idem, with covering flaps, Figure (W. D. Fig. 211 [197]) 53.288. - - i d e m, with only 2 tubes and covering caps 53.289. - - idem, with 1 tube only, Figure 53.290. Chemical Harmonica, after Dr. Bresina, Figure (Carls Bepertorium, 18, 1882, p. 84, and Ztschr. zur Forderung des physik. Unterr., 1884, p. 36), with 2 flames, and 3 burners on stand for analysing the flames 53.291. Gas Harmonica, Figure (W. D. Fig. 213 [199]), 2 m high, for showing the existence of overtones along with the fundamental tone, with burner for house gas and 6 conical open resonators of sheet zinc for the overtones g0, d1? bx, d2, f2 (sol,, re3, si3, re4, fa4) j 53.292. Pyrophone (W. D. Fig. 212 [198]), with one glass tube with two burners .... 53.293. Tube for Rijke's experiment (W. D. p. 269 [242]), on stand, with wire net and burner 53.294. Electric Harmonica, after Pflaum, Figs. A and B, for showing that the tone of the gas harmonica is not produced by successive explosions The tone is produced by an incandescent platinum win- net. shown plainly in Fie- 53,294 B. As the net is provided with suitable pieces for connecting up to the current it can easily be inter- changed. 53,294 B. Platinum Wire Netting alone, Figure £ s. d. 2.16.0 3. 4.0 2. 0.0 1. 6.0 3. 12. 0 2.1(1. 0 0. lli. 0 0. 15. 0 2. 10. 0 0. 15. 0 (1. 1073, 1068, 1067, 1070, 1071, 1072. No. 53301. Chemical Harmonicas (Singing Flames). Rotating Mirrors. 431 61 490. 1 : 10. 61 494. 1 : 8. 53 297. 1 = 6. 53 298. 1 : 5. 61491. 1:7. 53 301. 1 : 7. 52,031. Rotating Mirror Box (Cube Mirror), F i g. 52,031, p. 284, with mirrors 12 cm length and width, for placing on the whirling table, for demonstrating the flame images . . 61,490. --idem, with toothed-wheel drive, Figure 61,494. - - idem, with clockwork which can be regulated, Figure The speed can be regulated within very wide limits. 53.297. - - idem, with Electric Motor Drive, Figure, for connecting up to 2 volts and 8 amperes Direct Current The electric motor can be used also for explaining Ritchie's Top. 53.298. Rotating Mirror Box, larger, Figure, on stand, with mirror of 20 cm height and 12 cm width, for hand or cord drive 61,491. - - idem, driven by 110 volts Direct Current Motor, .Figure If the motor is required for a different kind of current or voltage the price is altered accor- dingly. 61,493. - - idem, with Alternating Current Synchronous Motor When ordering, the network voltage and frequency (number of pole-changes per second) should be quoted. 52,032. Rotating Mirror, after Eeichert, with circular mirror set obliquely; for placing on the whirling table (M. P. I, Fig. 648 [675]) 53,301. --idem, on stand, with clockwork, Figure Cl. 6029, 38«0, 1074, 3368, £ 8. d. 0. 13. 0 2. 10. 0 5. 10. 0 2. 4.0 1. 0.0 6.10.0 7. 0.0 0. 16. 0 2. 14. 0 1075, 5550. 432 Acoustics. No. 53302- 53 302. 1 : 9. 53 304. 1 : 6. 53 306. 1 : 4. 53305. 1:5. 53 307. 1 : 4. 53,302. Stroboscopic Disc, after Topler, with clockwork drive, Figure, for analysing oscil- lating planes, on stand 53,303. --idem, for hand drive £ s. (1. 3. 0.0 2. 0. 0 12. (». (i 53.304. Stroboscopic Disc, with 110 volts Direct Current Electric Motor and Tachometer, Figure, with series and shunt regulator for obtaining a wide degree of regulation If it is necessary to have a motor for a different voltage, kindly mention this when ordering. 53.305. Stroboscopic Disc, after Samojloff, Figure, for analysing sounds before a large audience (M. P., 10th Edn., Vol. I, Fig. 825), for use in conjunction with gas flame Manometer No. 53,306, which should be used with acetylene for this experiment. Tin- disc is placed on the whirling table (say, one with motor drive) and can also be used as a Siren Disc 0. 12. 0 The acetylene is generated from calcium carbide with the aid of a Kipp Apparatus, a smal gasometer being placed in front of the flame. 53.306. Gas Flame Manometer, after Weinhold, Figure, with rubber tubing and with resonator (W. D. Fig. 242 [228]) 0. 10. 0 53.307. -- idem, Figure, with rotating burner and driving device, can be used without rotating mirrors (W. D. Fig. 243 [229]) 1. 16. 0 Cl. 3369, 3949, £861, 4943, 1079. No. 53314. Stroboscopic Discs. Flame Manometers. Vibrating Bars. 433 53 309, 53 304. 1 : 8. 53 313. 1 : 6. 53 308. 1 : 8. 53 311. 1 : 9. 53314. 1:10. £ s. d. r>2,<>33. Gas Flame Manometer after Weinhold, as No. 53,307, suitable for the whirling table 1. 4. 0 .Vi.. 'iox. -- idem, Figure, with a rotating mirror; the two mounted on one stand . . 2. 0. 0 The manometer is constructed in accordance with Figure 53,306. 53.309. Mach's Organ Pipe for the stroboscopic demonstration of the vibrations of an air column, cf. Figure (M. P. I, p. 669 [739]), without stroboscopic disc or electric motor ' ">• The pipe has a membrane at the position of the nodal point corresponding to the fundamental tone; this membrane holds off the air current from the halves of the pipe, glazed on two sides, and situated between this nodal point and the end. A platinum wire is stretched in the interior of the pipe and connected with two external terminals, plainly visible in the Figure. If a small sponge, fixed on a glass rod and satu- rated with sulphuric acid is passed over the wire and the wire heated by an electric current, the vibrations can be observed from the vapours given off, by means of an intermittent light. Tne intermittent illu- mination is obtained with the Stroboscopic Disc No. 53 304 or with Tuning Fork No. 53 310. 53.310. Stroboscopic Tuning Fork c0 = 128 vibrations (ut2 = 256 v. s.), with electric drive, with two diaphragms, on stand Vibrating Bars, Velocity of Sound. 53.311. Apparatus for the Longitudinal Vibration of Bars, Figure (M. P. I, Fig. 761 [785]) 53.312. 4 Wood Bars, which sound a chord when thrown on the ground 2. 8. 0 4. 10. 0 0. 8.0 0. 3.0 53.313. 8 Wood Bars, giving the gamut, Figure 0. 6. 0 53.314. Apparatus for showing the Expansion and Contraction of a Longitudinally Vibrating Bar, after Koenig (Tyndall, Schall [Sound], Fig. 82) j 1. 16. 0 CI. 1116, 1117a, 1080, 5997, 6017. 28 434 Acoustics. No. 5331.>- 53 315 a. 1 = 20. 53316. 1:10. 53 317. 1 : 8. 53320. 1:6. 53 327. 1 : 3. 53,315. Kundt's Dust Figure Apparatus, for showing the longitudinal vibrations of bars and *•' for determining the velocity of propagation of sound in air (W. D. Figs. 214 — 21(1 [200 — 202]), with 4 screw ciamps and 2 glass tubes 1. Hi. o 53,315 a. --idem, Figure, the glass tube with mounts and unions without stopcock, in order to enable them to be filled with gases 1. Hi. o 5.'>, .'516. -- idem, Figure, the tube with mounts and stopcocks, but without screw chimps 1. 14. o 53,317. Apparatus after Quincke, Figure, for determining the Velocity of Sound by ob- serving stationary vibrations; on wood stand (cf. W.' u. E. Phys. Prakt. Fig. 87), with millimetre graduation on one side and plain two-colour centimetre graduation on the other side for measuring the length of the vibrating air column 1. s. o It is advisable to provide for use with the apparatus Tuning Fork No. 53,318 or 53,319. f>:i.:tix. 2 Suitable Tuning Forks for the above c., and c3 (ut4 and tit-,), on nxmancr box . Each £ 1.0.0 .">:). :)I9. — idem, without resonance box, with handle Each £ 0.18.0 53,320. 8 Steel Bars on one resonance box, Figure, giving the scale, with violin bow, for producing transverse vibrations of rods !.<>.(> cl. S033, 1114, 3800, 1122, 1120. No. 53 328. Dust Figures of Vibrating Air Colums. Tuning Forks. 435 53 326. 1 : 7. 53 328. 1 : 3. Tuning Forks and Accessories. We give special attention to the manufacture of tuning forks. The forks are, in accordance with the suggestions of the Physikalisch-Technische Reichsanstalt. Char- lottenburg, constructed of solid steel and calibrated against standard forks. The re- sonance boxes are prepared of suitable wood and each box is tuned to the tone of the fork. If desired, and on payment of the necessary fees, we send the tuning forks and boxes to the Physikalisch-Technische Eeichsanstalt for test and certificate. The fees are : for a standard fork ax = 435 vibrations, with box, £ 0. 3. 6 ; for a precision fork a1 = 435 vibrations, with box, £ 0. 5. 6; transit charges extra. Only those forks having the tone at = 435 compound vibrations (Ia3 = 870 v. s.) are certified as Precision Forks. The test fees for forks having a different number of vibrations vary from those quoted above. The number of vibrations are given in the following items as whole or compound vibrations, and, in addition (mostly in brackets) as half or simple vibrations, with the French abbreviation "v. s. == vibrations simples". The physical pitch is based on the tone ct = 2s = 256 compound vibrations (uts = 29 = 512 v. s.); the base of the International Pitch being the tone ax = 435 com- pound vibrations (^3-= 870 v. s.). 53.321. Tuning Fork a! = 435 compound vibrations (Ia3 = 870 v. s.), with handle, without box 53.322. Tuning Fork Cj = 256 compound vibrations (ut3 = 512 v. s.), large pattern, with handle, without resonance box . 53.323. -- idem, C2 = 512 compound vibrations (ut4 = 1024 v. s.) . 53.324. -- idem, g2=768 compound vibrations (so!4 = 1536 v. s.) . 53.325. -- idem, c3 = 1024 compound vibrations (ut5 = 2048 v. s.) 53.326. 12 Massive Forks with Stand, after Koenig, Figure (cf. Koenig, Quelques ex- periences d'acoustique, 1882, pp. 102 and 123), c3, c4, d4, e4, f4, 11th harmonic of c1? g4, 13th harmonic of c1? a4, 14th harmonic of c1} b,, c5 (uts, ut8, re6, mig, fa6, 11th harmonic of ut3, so!6; 13th harmonic of ut3, Ia6, 14th harmonic of ut3, si6, ut7) This set of tuning forks is used for showing that the vibrations of the first and second order become tones if they occur with sufficient intensity. The stand is arranged in such manner that two forks can be clamped for conveniently bowing or striking simultaneously. 53.327. 4 Tuning Forks, c,, c5, c6, c7, (ut6, ut7, utg, ut9), Figure, for demonstrating the limit of audibility 53.328. Tuning Fork, Figure (W, D. Fig. 258 [244]), of 2000 compound vibrations, for proving Doppler's Theorem Cl. 3375, 1125. £ s. d. 0. 4.0 1. 0.0 0. 18. 0 0. 18. 0 0. 18. 0 28.15.0 2. 8.0 1. 10. 0 28* 436 Acoustics. No. 53329 — 53333 (53334). 1 : 5. 53329 (53330). 1 : G. 53335. 1 : 6. 53337. 1 : 6. 53338. 1 : 12. 53.329. 13 Standard Tuning Forks in International Pitch, Figure,' in box, giving the £ s. d. chromatic scale cx to c2 (ut3 to ut4), without resonance box, with box for containing 9. 0. 0 53.330. — idem, physical pitch 9. 0. 0 53,331. 8 Standard Tuning Forks in international Pitch, same construction as above, giving the diatonic scale Cj to c., (ut3 to ut4), without resonance box, with box for containing 6.0. 0 6.0. 0 53.332. - - i d e m, physical pitch Resonance Boxes increase the price of the preceding Forks Nos. 53,329 — 53,332 by £ 0. 6. 0 each. 53.333. Tuning Fork with electromagnetic drive, c-! = 64 compound vibrations (utj = 128 v. s.), Figure, large massive pattern, with/ steel mirrors and counterpoise, on wood base 6. 0.0 53.334. -- idem, c0=128 compound vibrations (ut2 = 256 v. s.) •">. o. o 53.335. 2 Small Tuning Forks, Figure, ax = 435 compound vibrations (Ia3 = 870 v. s.), singly on resonance boxes, one with two sliding weights 0. is. o 53.336. 2 Small Tuning Forks C2 = .512 compound vibrations (ut4 = 1024 v. s.). on resonance box, one with two sliding weights 0. IS. o 53.337. 4 Small Tuning Forks on one Resonance Box, F i g u r e, for the tones c,. e,. g2 and c3 (ut4, mi4, so!4, ut5) 0. 16.o 53.338. 8 Small Tuning Forks, F i g u r e, each on a resonance box. giving the diatonic scale from {•., to c., (nt, to nts) 3. 12.0 53.339. 14 Tuning Forks on Resonance Boxes, Figure, giving the first 14 overtones to C-j^ 64 compound vibrations (ut, = 128 v. s.) 17.10.0 These tuning forks, like the overtone apparatus, serve for selecting easily the overtones when in- vest igat ing sounds with resonators or with the Koenig Apparatus for splitting up sounds. The individual forks are: c0 go ci ei gi cz d» e* gz bz 128 192 256 320 384 448 512 576 640 704 768 832 896 960 Compound vilnations 256 384 512 640 768 896 1024 1152 1280 1408 1536 1664 1792 1920 v. 8. ut, so!2 ut3 2nd 3rd 4th mi3 sol, — 5th 6'h' 7»> ut4 8'h gth IQth llih I2ili 13'1> 14tl> lf>'i> Partial Tone. CI. 3954, 11X1, 1126, 53S9, 3862. . 53373. Standard Tuning Forks. Tuning Forks with Resonators. 437 53339. 1 : 10. 53340 (53341). 1 : 7. 53,340. 2 Tuning Forks Cj = 256 compound vibrations (ut3 = 512 v. s.), large pattern, on accurately adjusted resonance box, one with two sliding weights, for producing vibrations Figure „ Together These tuning' forks have exactly the same pitch and are used for the experiment on co-vibration by resonance. The experiments succeed at a few metres distance if the open sides of the resonance boxes are turned towards each other and one fork is smartly struck repeatedly. 53.341. 2 Tuning Forks a! = 435 compound vibrations (Ia3 = 870 v. s.), Figure, same pattern as No. 53,340 Together 53.342. 2 Tuning Forks c., = 512 compound vibrations (ut4 = 1024 v. s.), same pattern as No. 53,340 . . . . " 53.343. 4 Large Tuning Forks, each on a resonance box, giving the major chord c,=256 .compound vibrations, e1? gx, c2 (ut3 = 512 v. s., mi3, so!3, ut4) 53.344. -- idem, with the fundamental tones C0 = 128 compound vibrations, e0, g0, ct (ut2 = 256 v. s., mi2, so!2, ut3) 53.345. 16 Tuning Forks on Resonance Boxes, cf. Figures 53,340 and 53,341, very massive pattern, Physical Pitch £ s. d. .2. 8.0 2. 4.0 2. 2.0 4. 16. 0 6. 0.0 21. 5.0 List No. 53 345 a £ 1. 10. 0 List No. 53 353 d,=576 53346 d1=288 re3 = 576 1. 10. 0 53 354 53 347 53 348 mi3=640 i.io.o 53 355 1. 10. 0 53356 g2=768 53349 g1=384 so!3 = 768 1. 10. 0 53357 53350 a1 = 4262/3 la3 = 853V3 1.5.0 53358 b,= 960 53 351 53 352 bt = 480 c2 = 512 vibrations si3 = 960 ut4=1024 v. s. 1. 5. 0 1. 5. 0 53 359 53 360 c,= 1024 c4 = 2048 vibrations re4=1152 mi4=1280 fa4=1365V3 so!4=1536 la4=17062/3 si4=1920 ut, = 2048 ut6 = 4096 v. s. £ 1. 5. 0 1. 5. 0 1. 5. 0 1. 5. 0 1. 5. 0 1. 5. 0 L 5. 0 1. 5. 0 Tnese forks are accurately constructed in accordance with Standard Forks and with carefully tuned boxes. 53,361. 13 Tuning Forks on resonance boxes, cf. Figures 53,340 and 53,341, very massive pattern, in International Tempered Pitch List No. 53 361 a 53362 53363 53364 53365 53366 ^ = 258. 652 c#! = 274. 033 dt = 290. 327 d*, = 307. 592 6i = 325. 881 f1= 345. 259 vibrations ut3 = 517.305 ut*3=548.066 re3=580.655 re#3=615.183 mi3=651. 763 fa3 = 690. 519 v. s. £ 1.10.0 1.10.0 1.10.0 i. 10.0 i.io.o 1.10.0 List No. 53 367 53 368 53 369 53 370 53 371 53 372 53 373 f*!=365.790 g, = 387.541 g#! = 410.585 a, = 435 ^, = 460.866 bj = 488.271 c2=517. 305 vibr. fa#3 = 731.580 sola = 775.082 sol* .,= 821.171 Ia3 = 870 la#3 = 921.733 si3=976.542 ut4= 1034. 610 v. s. £ 1. 10. 0 1. 10. 0 1. 10. 0 1. 5. 0 1. 5. 0 1. 5. 0 1. 5. 0 18. 10. 0 Cl. 1133. 6025. 438 Acoustics. No. 53374 — 53381. 1:6. 53382. 1:6. 53383. 1:4. 53398. 1: 12. 53404. 1 : 4. 53413. 1 : 5. Standard Forks on Resonance Boxes. List No. 53 374 53 375 53 376 a, = 435 lit, = 256 £ 2. 0. 0 ut3 = 512 1. 16. 0 la, = 870 53377 <•„= 512 utj = 1024 1. 10. 0 53378 f,= 1024 ut6 = 2048 1. 10. 0 53414. l : 7. 53379 c4 = 2048 compound vibrations ut6 = 4096 v. s. 1. 10. 0 £ 8. (1. 1. 10. 0 The Standard Forks are very specially and carefully constructed and finely polished to prevent oxidation. 53.380. Containing Box for one of the tuning forks Nos. 53,374 — 53,379 1. 53.381. Tuning Fork ct = 256 compound vibrations (uts = 512 v. s.), on Resonance Box. Figure, with detachable electromagnetic drive 2. 8. o 53.382. -- idem, &l = 435 compound vibrations, Figure (Ia3=870 v. s.) 2. 6. 0 .").;.. '583. 2 Large Tuning Forks, Figure, with sliding weights, on hollow wood base, tor producing the chromatic scale Cj — c2 (ut3 — ut4), International Pitch 3. 0. o 14 Tuning Forks with sliding weights, cf. Figure 53,383, for producing the tones and semi- tones from c 1tog3(utj — sol-), in International Pitch, for testing church bells for their 53387 ut., — mij 2. 4.0 53394 er-g+i ni4 — sol* 2.0.0 overtones. List No. 53384 53385 53386 Range ( of Tone I £ T C_i — (!#_! ut, — re#, 2. 10. 0 e-t— g , mi, — sol*i 2.6.0 g*-l— C0 SOI ti , Utj 2. 6. 0 List No. 53391 53392 53393 Rang< • i of Tone 1 £ GI — g i , mi3 — sol#3 2.4.0 sol*3 — ut« 2. 0.0 c.,— e, uti — mi, 2.0.0 53388 Co go mi.. — soh 2. 4.0 53389 go — b0 sol., — si.. 2/4. 0 53390 ut3 — mi, 2. 4.0 53395 53396 53397 iOl*4 Ut5 2.0.0 ut5 — mi, 2.0.0 mi6 — so!6 2.0.0 For testing a cliuivli l>dl ;^ rcicards it.- nvcrtcincs. .-i fork is struck and placed with the hollow li.-i-e on the edge of the bell. It the overtone is present the hell rings. {, 307 a. Containing Case for above, sufficient for 5 Forks 1. s. (i Cl. 1129 29a. 1123, 1134, 3376. '.132, 3374. Xo. 53417. Standard Tuning Forks on Resonance Boxes. Standard Tuning Forks with Sliding Weights. 439 53415. 1 : 8. 53417. 1 : 6. .">:•>.. 'JUS. Large Tuning Fork for 16 — 24 vibrations, c-3 — g-3 (ut-2 — sol-.,), F i g u r e, for deter- mining the limit of audibility of the deepest tones .~>3,3!Mi. - - idem, smaller Tuning Forks with sliding weight for Bezold's continuous progression of tones, for testing the sensitivity of the ear to sound, Figure 53,404. List No. < 'ompound vibrations V. s. Tone Compass j Pitch, unloadedj 53400 53401 53402 53403 53404 53405 12—18 16—24 24—36 36—55 55—90 90—153 24—36 32—48 48—72 72—110 110—180 180—306 — C-3— g-3 g-3— d-2 d_2 — a_2 a_2 — f#_! f*_! d*0 — Ut-2 SOl _2 sol_ 2 — re_j re_! — la_! la j — fa*i fa*! — re*2 — — C-i 8-1 c g . — — Utj solj ut2 so!2 4.0.0 3.0.0 2. 10. 0 2.5.0 2.0.0 1. 15." 0 These tuning forks sound without harmonics when the sliding weight is placed on same, and are used for qualitative and quantitative audibility testing from below the limit of audibility onwards; for the entire compass to the higher limit of audibility the entire continuous progression of tone (Bezold's) No. 53,473 is employed. The prongs of these tuning forks are marked with the number of vibrations and the tones for the cm responding positions of the sliding weights. List No. 53406 Compound vibrations 153 — 217 V. s. 306—434 _, ( d# — a Tone Compass ( re# la Pitch, unloaded i £ ut3 1.5.0 53407 53408 53409 53410 217—307 307—435 435—615 615—870 434—614 614—870 870—1230 1230—1740 a — d#! d#! — ax a! — d#2 d#2 — a2 Ia2 — re* 3 re#3— Ia3 Ia3 — re*4 re*4 — Ia4 so!3 ut4 so!4 ut5 1.0.0 1.0.0 1.5.0 1.5.0 The prongs of these forks are marked with the tones for the corresponding positions of the sliding weight. £ s. d. 12. 0. 0 10. 0.0 :> 1.411. Drumstick for striking Tuning Forks Nos. 53,406—53,410 0. 5. 0 .VI. 112. Tuning Fork bb, (si"3), for resonance of the oral cavity (W. D. p. 312 [285]) . . 0. I.u 53,413. 5 Tuning Forks with resonators, Figure, sounding with the vowels a, e, i, o, u 7. 0. 0 5:3,414. Tuning Fork with Resonator, Figure, pitch aj with 435 compound vibrations (ut3 = 870 v. s.), the tuning fork is marked with the nodal point (W. D. Fig. 217 [203]) o. ir>. (i 53,415. Standard Fork with Resonator, Figure, mounted together on iron base, ct = 256 compound vibrations (ut3 = 512 v. s.) 5. o. o .").'•). 4 17. Tuning Fork with Electromagnetic Drive and with sliding weights, for varying the pitch by reducing the size of the orifice, with resonator of variable pitch F i g u r e 5. 0. 0 The tuning fork can be adjusted to the tones between d*j and al (re#3 and Ia3). The pitch of the is varied by an iris diaphragm placed in front of its aperture. Cl. 1135, 3894. 440 Acoustics. No. 53418 — 53418. 1 : 5. 53420. 1 : 5. 53421. 1 : 5. 53425. 2 : 3. 53426. 1 : 8. 53429. 1 : 12. 53.418. Recording Tuning Fork C0 = 128 compound vibrations (at., = 256 v. s.), with style, Figure l>Yr<>rding Tuning Forks with electric drive, chronographically, see p. 455. 53.419. Shoe with Writing Point for Fork No. 53,382 (M. T. Fig. 36) 53.420. Ivory Hammer for striking Tuning Forks, Figure 53.421. Hammer with rubber strikers, Figure 53.422. Metal Drum Stick with leather discs 53.423. Cello Bow 53.424. Bass Fiddle Bow, can be used for experiments with heavy tuning forks 53.425. Tuning Fork Exciter Clamp after Db'lger, F i g u r e, to enable the tuning forks always to be vibrated to the same intensity, with screw adjustement, rule, and in box . . . Vibrating Strings, Plates, Bells, etc. 53.426. Monochord, Figure, useful string-length 1.2 m, with 3 strings, 2 with pegs and one with weight for stretching, with centimetre scale, movable bridge and damper clamp. of polished mahogany (only two strings are shown in illustration), without weights . 53.427. -- idem, of alder wood, same .-i/.e as above, simpler pattern i S. (I. 0.18.0 0. 3. 0 0. !). 0 0. !>. o 0. (J. 0 0. 4.0 0. »;. u 1. 15.0 1. 11'. 0 1. 4.0 cl. 1124,3378,4519, 51)27, 1149, 1150. No. r>3436. Accessories for Tuning Forks. Monochords. 441 53431. 1:15. 53434. 1 : 9. 53436. 1 : 10. 53,428. Monochord. smaller and simpler, with two strings stretched from pegs 53,429. Monochord with 4 Strings, two stretched by pegs and two by weights , F i g u r e, on iron legs 53.430. 4 Iron Weights with Hooks, 20, 10, 5 and 1 kg, for stretching the centre strings (W. D. p. 279 [253]) If the above Monochords are desired to be divided in millimetres the price is increased by £ 0. 15. 0 each. 53.431. Monochord for School Use, after Hahn, Figure (Halm, Schiileriibungen Fig. 155), with spring balance and striking hammer 53.432. Tuning Fork for above, with groove in the base of the fork handle, c, = 256 compound vibrations (ut3 = 512 v. s.) .Vi.433. — idem, dl = 288 compound vibrations (re3 = 576 v. s.) .• 53,434. Polychord after Antolik, Figure, with 12 strings, iron frame and stretching device Two metal rails are arranged laterally on the iron frame of the Polychord, and clamps can be slipped along the rails. Each clamp has a compression cheek with the aid of which the lengths vibrating ran be shortened to any extent. Tne length is read off on two metal rules. Trie apparatus can be. used advantageously for forming musical scales. See: Tonleitersystem von Prof. Dr. Karl Antolik, Pressburg, and Ztschr. f. d. phys. u. chem. U. 4, 1890/91, p. 177). 53,435. 10 Riders of Aluminium Wire, after Antolik, for the Monochord £ s. d. 0. 15. 0 3. 0.0 1. 2. i) 0. 12. 0 0. 10. 0 0. lo. o 20. 0.0 0. 1. 0 53,43(>. Monochord after Zahlbruckner, Figure, with two strings, with tension indicators. • Can be used also as a Tensile Apparatus to 50 kg pull, for metal wires, etc. With 4 bridges |17. 0. 0 The two metal strings are connected at one end with spring dynamometers for 50kg tension and at the other end with stretching devices actuated by worm gearing. The tensive forces exerted on the dynamo- meters can be read off on a scale. In order to render the measurements accurate the bridges are lifted by wedges only when the strings are stretched. A plain centimetre scale is fitted on the side of the re- sonance box for showing the position of the bridges. (.']. 5053, 1151, 1152. 442 Acoustics. No. :>3437- 53 441 A. 1:6. 53438. 1:4. ^ 53 441 B. 1:6. 53443 and 53 441 C. 1: 9. 53 445. 1 : 6. 53452. 1:3. 53. 437. Apparatus for showing the position of the Nodes on the opposite sides of a longitudinally - vibrating Horse Hair 0. 6. o 53.438. Apparatus for Chladni's Figures, Figure, consisting of one iron clamp, one rectangular and one round glass slab 28 cm diameter, in box with sand and case of resin (W. D. Fig. 220 [206]) 1. 2.0 53,43!). - - idem, with two Metal Discs of 28 cm diameter or length of side respectively 1. 8. 0 53.440. Black Board for No. 53,438, for showing the dust figures in air plates (W. D. p. 285 [258]) 0. 1.0 53.441. Chladni's Sound Figure Disc, of metal, Figures A and B, see also Figures 53,443 and 43,441 C, with heavy iron base, round, rectangular or triangular, 30 cm dia- meter or length of side . Each 1. i>. o 53,153. Mirror on Stand, Figure 51,153, p. 206 (M. T. p. !>), for rendering the sound figures more visible 1. S. o .V..143. Tube with Stand for Chladni's Discs, for Ilopkins's Experiment on Resonance, Figure 53,443, without sound figure disc (). IS. (I 53.444. Sound Figure Disc with Resonance Tube for Ilopkins's Kxpcriment. fitted together on massive base 1. Hi. o 53.445. 2 Metal Discs of same shape, Figure, one with foot, the other with handle . . 1. 10. (I These plates are of the same pilch. If the one with the handle is bowed and held above the other, the latter shows the same figure by resonance. 5.".. I Hi. Brass Plate with steel mil attached for concentric nodal lines (M. 1'. I, Fig. 736 [76<>|) o. 1'J. (I 53, 117. Square Paper Membrane, 30 cm side, on support with wind tube 1.16.0 53. 14'.!. Round Paper Membrane of 3d cm diameter, for above o. o. o Cl. 1155, 1154. 1156,59111. 5998, 5010. No. 53459. Sound Figures. Resonance Phenomena. 443 53 453. 1 : 6. 53454. 1:9. 53 456. 1 : 7. 53455. 1:1-2. 53458. 1:10. 53459. 1:8. £ s. d. 5.5,450. Triangular Paper Membrane for preceding, length of side 30 cm 0. 6. 0 53, 151. 3 Small Paper Membranes, round, rectangular and triangular, for preceding ... 0.10.0 53,452. Powder Spray, Figure, for powdering the colour figure discs 0. 5. 0 With the aid of the above the discs can be coated quite evenly with lycopodium. 5.3,453. Apparatus for showing the Vibration of Liquid Films, Figure, with three metal plates of round, rectangular, and triangular aperture 1. 2. 0 53.454. Glass Bell on wood base, Figure, for showing the nodes 0. 4. 0 The bell is filled with water and when sounded shows the vibration-nodes by a rippling of the liquid. 53.455. Glass Bell with 4 Pendulums in contact with its periphery, Figure, on stand . 1. 4. 0 Resonance Phenomena. Organs of Human Speech and Hearing. * 53,456. 2 Tuning Forks, one with small pendulum, Figure, on resonance box, ct=256 (ut3 = 512 v. s.), for showing the resonance of this tuning fork when the other, of the same pitch, is struck (Ztschr. f. d. phys. u. chem. U. 7, 1894, p. 272) ! 2. 12. 0 53.457. Cylindrical Glass, 1 m high, for showing resonance (M. P. 9lh Edn. I, Fig. 663) . . 0. 8. 0 The cylindrical glass is filled with water to such height that the air column above corresponds to a tuning fork set into vibration and held over a glass; use can be made, say, of a, (ut:)). 53.458. Resonance Apparatus after Savart, Figure (M. P. I, Fig. 638 [665]) 2. 4. 0 The glass bell is made to sound by stroking with a violin bow and the resonator tube (in two parts) is varied until resonance takes place. 53.459. Resonance Apparatus after Drenteln, Figure, consisting of a tall glass cylinder, forming the source of sound, a lamp glass, closed on one side, as resonator, a brass tube for blowing the cylinder and a small lamp (Ztschr. f. d. phys. u. chem. U. 7, 1894, p. 273) • 0. 6. 0 By blowing aside cork dust or lycopodium. spread on the inner edge of the glass resonator, or by blowing out the lamp, resonance is shown, when the cylindrical glass is blown with the blowing tube, after its tone is timed to the tone of the resonator by filling with water. * Can be used with the Pro- jection A]>i>aratu>. Resonators for Sound Analysis, etc. see p. 449 — 451. Cl. 6031, 5792, 4974, 6000, 1046, 5859. 444 Acoustics. \i. ..1461 — 53462. 1 : 3. 53464. 1 : 4. 53469. 1 = 9. 53463. 1 : 4. 53471. 1 : 7. Membrane Pipe serving as model of the Larynx: see No. 53,281 (cf. W. D. Fig. 225 [211]) 53.461. Model of Larynx, after Bock, simple 53.462. - i d e m, with hyoid bone, Figure 53.463. - idem, with view of the pharyngeal space and nasal cavity, Figure . . . 53.464. Model of Ear, Figure, can be taken entirely apart, very carefully constructed. five times actual size 53,465. - idem, ten times actual size 53,468. 4 Steel Bars, c,, c6, ce, c7 (utg, utv. utg, ut9), lor testing the upper limit of audibility, in case (M. P. I, Fig. 679 [705]) 53,461). 5 Steel Bars, c4, c5, c6, c,, cg (utg ,ut7, ut8, ut9, ut,0), F i g u r e, for the same purpose, with suspension and steel hammer 53,470. 10 Steel Cylinders, cs, es, gs, c6, e?, g6, c7. c:, g7. c8 (ut7. mi7, solT. utH. mis, sol,, ul,,. mi9, sol,,, lit,,,), for testing the upper limit of audibility, with steel hammer, cf. Fig. .VS. I , 1 53.47.1. 22 Steel Cylinders, from c- to <•„ (lit, — u1,n), for the same purpose. Figure, with steel hammer . 4 Tuning Forks for showing the upper limit of audibility, see Fig. 53,327, p. !•"•"> Large Tuning Forks lor shouini: the lower limit of audibility: sec \os. .vs. :i!is .- ;,:!. mo, |>. 439. Cl. 1192, 1194. II 113. 6001. £ 8. d. 0. 5.11 0. (i. d (I. IS. 0 0.15. 0 0.12. O 0. 15. 0 1. 4.0 I. Ul. 0 3. 10. 0 7. II d L'. S. 0 1118. No. .'.3480. Models of Larynx and Ear. Limit of Audibility. 445 53473. 1 : 8. 53480. 1 : C. 53478. 1 : 2. 53.473. Bezold's Continuous Progression of Sounds Apparatus, Figure, for investigating the tone-sensitivity of the ear, consisting of 10 tuning forks with sliding weights Nos. 53,401 to 53,410, for the compass c-3 — a2 (nt-2 — Ia4), 1 drum stick No. 53 411 for the forks, each one pipe Nos. 53,476 and 53,477 for compass e> — a4 (mi4 — Ia6) and a Galton's Whistle No. 53,479 of compass a4 (Ia6) onwards to beyond the limit of audibility; I lie whole in box, the Galton Whistle being contained in a separate case Further particulars as to the individual tuning forks are given on p. 439 and for the pipes, below. 53.474. Additional Series of unloaded Tuning Forks for the tones g3, c4, g4, c5 (so!5, ut6, sole, ut7), with drum stick and case r)3,475. Further complementary series, comprising a loaded tuning fork No. 53,400 for 12 — 18 compound vibrations, and unloaded forks a0, a1? and n., (Ia2, Ia3, Ia4) ....... 53,476. Pipe for the Higher Tones of Bezold's Continuous Tone Progression, large, for the tones between e2 and a3 (mi4 and Ia5) . . •").">. 177. -- idem, small, for the tones between a3 and a4 (Ia5 and Ia6) •V>. 178. Galton's Whistle, F i g u r e, for producing the highest tones and 'for demonstrating the higher limit of audibility, simple pattern ."•3. 179. - - i d e in, new improved pattern, Figure, for the tones from ;ij (Ia6) to beyond tlie limit of audibility (3480 — 30,000 compound vibrations), in case • 53,480. Dust Figure Apparatus for Galton's Whistle, F i g u r e, consisting of screw clamp and 6 different glass tubes C1.4702, 3372, 11-21. £ s. d. 22. 10. 0 4. 15.0 4. 0.0 2. 5.0 1.15.0 0. 16. 0 2. 15. 0 0. 10. 0 4698, 446 Acoustics. NIL 53481 53 500. 1 : 6. 53 485. 1 : 4. 53486. 1:7. 53492. 1:4. Tonometric Apparatus and Resonators. Tone Variators after Prof. Stern, Figures 53,485, 53,486, cf. also Fig. 53,506, the tone being varied steadily and uniformly (Ztschr. f. Psychologic und Physiologic der Sinnes- £ s. (1. organe, Vol. 30, 1902, List No. 53,481 Size 1 , p. 422). 53,482 2 53,483 3 53,484 4 53,485 5 53,486 6 53,487 7 Compass / From I To 100 165 150 300 200 400 300 600 400 800 500 1000 600 ) 1200 ) compound vibrations £ 8.0.0 7. 10. 0 6. 10. 0 6.0.0 6.0.0 6.0.0 6.0.0 The apparatus is suitable for demonstration purposes and for tuning, for psychological investi- gations and practical investigations by otologists. The tone variators are brass flasks with zinc cap and blowing tube. The flasks have an adjustable bottom which is raised by a spiral shaped disc in such manner that equal angles of rotation of the disc correspond to approximately the same variations in periodicity. The periodicities can be ivjnl off direct on the dial. In addition to the values of the periodicities, the musical tones in International Pitch are given on the dial. Calibration is made by means of the blowers listed under Nos. 53,229 and 53.230. these blowers supplying a very uniform pressure. It is advisable to use such a blower for the tone variators so that a uniform pressure may be introduced into the apparatus. For observing the pressure when blowing every tone variator is provided with a pressure gauge on the scale of which is marked the pressure at which the tone variator is adjusted. The formation of a progression of tones from the single flasks can be introduced at the wish of the customer. It is advisable to select the flasks so that the successive compasses of tone partially overlap, since it is necessary in a number of experiments to sound two similar or closely adjoining tones simul- taneously. An accurate description is appended to each apparatus. Prof. Stern, simple pattern, Figure, suitable for demonstration Tone Variators si ft or purposes only. Compass In this apparatus the bottom of the pipe is not displaced by :i spiral, but by rack and pinion. An excentrically operated pointer indicates the number of vibrations on the scale. 53,495. Tonometer No. 1 of 33 tones: Fundamental Tone C0 = 128 compound vibrations to ct = 256 (ut2 = 256 v. s. to uts = 512 v. s.), each BUCCeding tone about four compound vibrations higher than the preceding !'. n. The Tonometers and Overtone Apparatus fit all our Blowing Tables. List No. Size J From 53,488 8 100 53,489 9 150 53,490 10 200 53,491 11 300 53,492 12 400 53,493 13 500 53,494 14 600 ) compound I To 165 300 400 600 800 1000 1200 j vibrations £ 6.0.0 5. 10.0 4.10. 0 4.0.0 4.0.0 4.0. 0 4. 0.0 •**> Please observe also die Hezold's Continuous Tone-Progression Apparatus, No. 53.473. also the single tuning forks and pipe* for same. (I. 1109, 1112, 5819, 1112«. No. 53502. Tonometric Apparatus. 447 53 497. 1 : 10. 53 501. 1 : 6. 53.496. Tonometer No. 2 of 65 tones: Fundamental tone c0 = 128 to c, =256 compound vi- brations (ut, = 256 v. s. to ut3 = 512 v. s.) each succeeding tone about two compound vibrations higher than the preceding 53.497. Tonometer No. 3 of 65 tones, Figure: Fundamental Tone cl = 256 to c2 = 512 com- pound vibrations (ut3 = 512 v. s. to ut4 = 1024 v. s.), each succeeding tone about four compound vibrations higher than the preceding 53.498. Tonometer No. 4 of 129 tones: Fundamental Tone ct = 256 to c2 = 512 compound vi- brations (ut3 = 512 v. s. to ut4 = 1024 v. s.), each succeeding tone about two compound vibrations higher . . 53.499. Tonometer of 129 tones: Fundamental Tone c3 = 512 to c3 = 1024 compound vibrations (ut4 = 1024 v. s. to uts = 2048 v. s.), each succeeding tone about four vibrations higher 53.500. Overtone Apparatus, Figure (W. D. Fig. 224 [210]), consisting of 9 reed pipes with wind chest and wind regulator, for the 1st to 9th overtone of c-, = 64 compound vi- brations (ut! = 128 v. s.) Resonators for above: see pp. 450 and 451. 53.501. - - i d e rn, Figure, the first 32 overtones of c-! = 64 compound vibrations (utj = 128 v. s.) to c4 = 2048 (ut6 = 4096 v. s.) with wind chest and air regulation. If desired we also supply overtone apparatus for other fundamental tones. 53.502. Interval Apparatus after Htumpf, with 20 tones in the compass of an octave and funda- mental tone of 400 compound vibrations (800 v. s.) In addition to the fundamental tone (1:1; 400 compound vibrations) the apparatus has: chro- matic second (25 : -24; 410.66), minor second (16 : 15; 426.66), major second (9 : 8; 450), Pythagorean minor third (32 : 27; 474.1), tempered minor third (363 : 305; 476), pure minor third (6 : 5; 480), pure major third (5 : 4; 500), tempered major third (635 : 504; 504), Pythagorean major third (81 : 64; 506.25) pure fourth (3 : 4; 533.33) augmented fourth (45 : 32; 562.5), tempered fifth (2655 : 1772; 599.3), perfect fifth (3 : 2; 600), perfect minor sixth (8 : 5; 640), perfect major sixth (5 : 3; 666.66), natural seventh tone ,,i" (7 : 4; 700), minor seventh (9 : 5; 720), major seventh (15 : 8; 750), and octave (2:1; 800). £ s. d. 15. 0.0 15. 0. 0 22. 10. 0 22. 10. 0 4. 4. 0 9. 0.0 7. 10. 0 Cl. llll, 1110. 448 Acoustics. NIL 53506 (53230, 53231, 53503, 53482, Tone Variator 275 550, 53485, 53487, 53282). 1 : 12. r>.'5,r>o:5. Interval Apparatus and Tonometer after Prof. Ebbin»;haiis. cf. Figure r>:5,r»o<» (the box-shaped apparatus in the forejjround of the table), with 22 interval tones within an octave, having the fundamental tone of 400 compound vibrations (800 v. s.) with 28 tones for tone-measuring at corresponding intervals between .'50 and 1600 compound vibrations (60 and 3200 v. s.) and with 16 tones for tone-measuring between the fundamental tone of 400 compound vibrations (800 v. s.) and its major second . . The following reed pipes are fitted for demonstrating the intervals: fundamental tone (1:1: 4(M» augmented fourth (%•' , : 1: 502.5), tempered fifth cjli.Vi : 177-2: r,!t!l.:!). perfect fifth (3 : '2: (ioo). perfect iiiinor sixth (8 : 5: (i4n). perfect ui:ijor sixth (5 : 3:666.66), natural seventh (7 : 4:700). seventh i1 .. • ' :, : 1 : 711.1), minor seventh (!( : 5: 72u). major seventh (15 : 8; 750) and the octave i •_' : I: son). s. d. IS. 0.0 pipes mentioned above can lie used in part for tonometric purposes: for this special purpose has reeds with :i(i. 4o. .VI. (in. To. so. !tn. Inn. |-2(i. I L>r>. l.Vi. 1 no. -2011. -2 in. I'.Vi. :inu. :\2(>. The reed the ii]iparatns has 3liO. 4(1(1. 48(1, 50(1, (>(Kl. sun. linn. '.Kill, lllllll. 1-20(1. Kidll compound vibrations. Cl. 4139. NIL ••3511. Interval Apparatus, Triad Apparatus, Resonators. 449 53507. 1:7. 53508. 1:6. A! so with 404, 408, 412, 416, 420, 424, 428, 432, 436, 438, 440, 442, 444, 446, 448, 449 com- pound vibrations. As blower for this apparatus the most suitable to use is the blowing table for constant pressure, No. 53,229, or the Whipple Double Blower, No. 53,230, with wind chest and Table No. 53,231. 53.504. Triad Apparatus, after Prof. Stumpf, Berlin, for demonstrating the major and minor triad at four different positions With this apparatus it is possible to demonstrate the major triad (4:5: 6) and the minor triad (10 : 12 : 15) iii four different pitches, and to determine by this means the pitch which forms the most perfect harmony. The chords are based on a frequency of 100. Number of vibrations: (a) 100, 120, 125, l.">0; (b) 200, 240, 250, 300; (c) 400, 480,500, 600; (d) 800, 960, 1000, 1200; as complements for the difference-tones and overtones: (e) 80, 160, 640, 720; (f) 700, 900, 1100. 53.505. Triad Apparatus of 24 Massive Tuning Forks on Resonance Boxes Fequencies: 100, 120, 125, 150; 200, 240, 250, 300; 400, 480, 500, 600'; 800, 960, 1000, 1200; 1600, 1920, 2000, 2400; 3200, 3840, 4000, 4800. 53.506. Acoustic Apparatus after Prof. Ebbinghaus, Figure, comprising Whipple Double Blower No. 53,230, a Wind Chest with Table No. 53,231, and Interval Apparatus and Tonometer after Ebbinghaus No. 53,503, one each Tone Variator after Stern for .150 — 300 compound vibrations No. 53,482, for 275 — 550 compound vibrations (by special arrangement), for 400 — 800 compound vibrations No. 53,485, for 600 — 1200 vi- brations No. 53,487, and a Eeed Pipe with sound horn and deep tone c_x = 64 compound vibrations (utx = 128 v. s.) No. 53,282 As to the individual apparatus, kindly refer to the text under the List Nos. given. 53.507. 3 Resonators, Figure, of different shape (spherical, conical, and prismatic), of different material (glass, pasteboard, wood) and of different pitch (g1( e1 ut.,) c, ; sol,, mi •3) 53,508. Resonance Tube on Base, can be closed at one end, Figure With this resonance tube, which replapes the labial pipe, it is explained that when the pipe is open the overtones are the even quadruples of the fundamental tone, and when the pipe is closed, that the overtones are the odd quadruples of the fundamental tone, and that the fundamental tone of the open pipe is the octave of the fundamental tone given by the covered pipe of equal length. The open pipe vibrates therefore in a half wave, the covered pipe in a quarter wave. Tne lube is tuned in such manner that when closed on one side it gives the fundamental tone ct (ut3) clearly and resonantly. For this purpose the tuning fork Cj (uts) is struck smartly and held in front of the free aperture. Even with tuning fork g2 (so!4) (the overtone with thrice the number of vibrations) the tube resonates clearly, while it does not resonate with fork c2 (ut4), the octave of the fundamental tone. Tais, however, becomes the case when the resonator tube is opened so that it corresponds to the open labial pipe, which gives a tone twice as high as the covered pipe of the same length. .->:>. .in!). Tuning Fork for above, Ci = 256 compound vibrations (ut3 = 512 v. s.), with handle .").'{..") 10. — id em, c2 = 512 compound vibrations (ut, = 1024 v. s.), with handle .">:'.. ."ill. — idem, g, = 768 compound vibrations (sol, = 1536 v. s.), with handle 30. 0.0 £ s. d. 9. 0. 0 74. 6. 0 0. 12. 0 1. 8.0 o. o 18. 0 18 0 Cl. 4693, 1105. 29 450 Acoustics. No. 53512- 53518. 1 : 6. 53.282. Reed Pipe, Figure 53,282, p. 429, with sound horn, c_1 = 64 compound vibrations £ * (1 (ut1 = 128 v. s.), deep tone 1. 10th overtone of c.j (ut,) l.lo. 0 53.513. - - i d e in, closed 1. 12. 0 53.514. 11 Cylindrical Resonators, of pasteboard, Figure, covered, for the 2nd to 12th pai t ial tone of c_! (utx) 1. 0. 0 53.515. 15. Resonators for Pipe No. 53,282, conical, covered, from 1st to 15th overtone (2nd to 16th partial tone) of c_t (utj 2. 5. o 53.516. 19 Resonators for Pipe No. 53,282, after Ilolmholtz, Figure, spherical, for the first 19 overtones of c_! = 64 compound vibrations (utj = 128 \ . s.), guaranteed accurate in tone and well constructed, on board, with wood handles 7. 10. o The resonators are constructed of stout sheet brass and accurately adjusted. In view of its bulky nature the fundamental tone is not included in the sei. 53.283. Reed Pipe with Hound Horn, of. Figure 53,282, p. -129, e0 = 128 compound vibrations (ut2 = 256 v. s.), with deep tone 1. (I. (I. 5311, 5445, 1107,5033. No. 53 523. Resonators. Frequency Curves. 451 53519. 1 : 8. 53521. 1 : 8. 53 522. 1 : 8. 53.517. 10 Resonators for preceding, after Helmholtz, Figure, spherical, in perfect tone, £ s- d. for fundamental tone c0 = 128 compound vibrations (ut.2 = 256 v. s.) and its first nine overtones, on board, with wood pegs 5. 0. 0 In this set of resonators the fundamental tone c0 (ut2) (first partial tone) is not included. 53.518. 14 Universal Resonators after Konig, Figure, consisting of two cylinders sliding one in the other, with graduation, to be employed for all tones from g-l (solj) to es (mi5), the tones of the chromatic scale being indicated singly 18. 0. 0 The compass of the individual resonators is as follows: (1) g_, to b-, (so^tosi,); (2) b_, to d*0 (sij to re*2; (3) d*0 to f*0 (re*2 to fa*2); (4) M=0 to a0 (fa*2 to Ia2); (5) a0 to ct (Ia2 to ut3); (6) cl to et (ut3to mi3); (7) e^o at (mi3to Ia3); (8) aisj to d2 (la*3 to re,); (9) c, to e. (ut4 to mi4); (10) d2 to f2 (re4tofa4): (11) e2 i to g*jj (mi4 to sol*4); (12) L, to a2 (fa4 to Ia4); (13) g*2 to c3 (sol*4 to uts); (14) c3 to e3 (uts to mi5). ! Demonstration of Lissajous Curves. * 53,519. Apparatus for Demonstrating the Lissajous Curves by Crank Motion, Figure, for projection as well as for drawing the curves on blackened glass plates (Fr. phys. Techn. 1, 2, Fig. 3393 [I, 494]; W. D. Fig. 234, 220), with wheels for obtaining the ratios 20, 24, 30, 36, 40, 48, 50, 59 and 60 : 60 4. 4. 0 53.520. Kaleidophone after Wheatstone, simple, one steel bar with spherical mirror on metal base (M. P. I, Fig. 704, 728) 0. 10. 0 53.521. Kaleidophone (Wheatstone's), Figure, with 6 rods having spherical metal mirrors, on iron stand with levelling screw, for producing 6 phases (M. P. I., Fig. 706 [730]) 2. 10. 0 When struck, the differently shaped rods give directly the corresponding Lissajous curves The figures shine well and large on the ceiling under incident light. 53.522. Universal Kaleidophone, after Melde, Figure, with adjustable metal strips and spherical metal mirror (M. P. I., Fig. 707 [731]), with screw clamp 1. 10. 0 52,124. Double Pendulum after Airy, Fig. 52,124 A and B, pp. 296 and 297 1. 0. 0 53.523. Pendulum Apparatus for obtaining the vibration curves of Wheatstone and Lissajous, Figure (Eisenlohr, Lehrb. d. Phys., Fig. 181) 1.16.0 * Can be used with the Projection Apparatus. Cl. 5842, 6032, 6008, 4014. 29* 452 Acoustics. No. 53524- 53 524. 1 : 5. 53 528. 1 : 7. * 53,524. Apparatus for Demonstrating the Lissajous Figures by means of vibrating springs with mirrors, Figure, with electromagnetic drive in order to maintain the vibrations to any length of time 4. 16. 0 53,525. - - idem, without electromagnetic drive . 2. 0. 0 * 53,526. - - idem, after Pfaundler, with two vibrating steel springs and crossed gaps (M. P. I, Fig. 702 [726]), one spring with variable time of vibration i 1. 4. 0 53.528. Electric Glow Lamp with straight Filament, Figure, on stand, with shielding chimney and small hole, for use with preceding apparatuses or with the following Tuning- Fork Apparatuses 0. 18. 0 The working voltage should be quoted when ordering. If this is not given we supply the lamp for 110 volts. 53.529. Tuning Fork Apparatus for subjectively and objectively demonstrating the Lissajous Curves (W. I). Fig. 236 [222]), with two massive tuning forks <•„ = 128 compound vi- brations (ut., = 256 v. s.), one fork with sliding weights, with glass mirrors, on polished wood stand 5. 0. 0 53.530. The same Apparatus, Figure, both forks with electromagnetic drive 8. 0. 0 53.531. The same Apparatus, with thoroughly well ground steel mirrors, without electro- magnetic drive (i. 0. 0 32. - idem, with steel mirrors and with electromagnetic drive for both forks . . 0. 0.0 Tuning Forks for above for demonstrating the curves (Lissajous) of varions phase-differences (M. P. 1. l-'ig. 71!i). 53,533. Phase Differences, 1 53,534. 53,535. 63,536 63,638. 53,53!). 1 2, ct = 256 1 3, gu= 384 2 3, go= 192 3 4, f0= 17d= ;, 3 5, ao= 213' ., 4 5, ea = 160 5 6, a , = 1062/3 Compel Vib., (a) With Steel Mirror uts = .-> 1 2 v. s. £ 1. Hi. 0 SOl 3 = 768 v. B. £ 1. 16. 0 so!2 = 384 V. s. £ 1. 16. 0 fa2 = 3 1 1 ' ., V. s £ 1. 16. 0 Ia2 = I2fi- , v. B, £ 1. 16. (I mi2 = 320 V. B. £ 1. 16. 0 laj = 213-/3 V. 8. £ 2. 0. 0 (b) With (Mass Mirror hi. i) in. (i Hi. ii in. ii Ki. (i in. ii 14. 0 Tiic forks listed give together with one of the forks <•„ = 128 compound vibrations int, '-'."ili v. s.) of the Apparatus No. 53,529 — 63,632, tne pha.-.e differences mentioned. 53,540. 2 Tuning Forks on Stands, mounted vertically and the Forks provided with glass * s (> v. s.). one' in a horizontal and the other in a vertical position. Tne Tuning Forks have limbs -J.'id mm buig and give * Can lie used with the Projection Apparatus. CI. 3890, 3875. No. 53542. Frequency Curves. Tuning Fork Apparatus. 453 53530. 1:6. 53 542 A. 1:10. 53541. 1:6. 53542B. 1 : 10. large vibrations. Tney are provided with steel mirrors and adjusted at 20° C. Both forks nave electro- magnetic drive. By means of two sliding weights one fork can be put out of tune for producing tremors. By aid of the Projection Lantern and a Lens the curves can be very beautifully projected on to a screen. * 53,542. - - i d e in, with arrangement, in addition, to enable compound parallel vibrations to be objectively demonstrated, with two diaphragms on one fork and a string support on the other, one Stand, Fig. A, and a Lath on which a catgut cord is to be stretched, Figure B The five following very beautiful experiments can be carried out with the apparatus: (1) Subjective observation of the Lissajous Curves (M. P. I, Fig. 688 [712]); (2) Objective demonstration of the Lissajous Curves on the sc.?en by means of the Projection Lantern; (3) Objective demonstration of the sine curves produced by compound parallel vibrations (M. P. I, Fig 808 [832]); (4) Observation of the Vibrations of a Fork by Mach's Stroboscopic Method (M. P. I, p. 668 [738]); (5) Observation of the vibrations of string by the same method (M. P. I, p. 670 [740]). Complete description is appended to the apparatus. Stroboscopic Disc driven by Electric Motor, for observing the condition of vibration - - see under No. 53,304, p. 432 £ s. d. 15. 0. 0 12. 0. 0 * Can be used with the Projection Apparatus. Cl. 1137. 1139, 1138, 1110. 454 Acoustics. No. 53 543 — 53 560. 1 : 5. 53 543. 1 : 7. 53 544 B. 53 544 A. 1:8. 53,543. Tuning Fork Apparatus as No. 53,592, F i g u r e, new Model, with fork-holder capable of reciprocal rotation * 53,544. Large Tuning Fork Apparatus, K i g u i • <• s A and B, for subjective and objective Demonstration of the Lissajous Curves, and for the graphical demonstration of the vibrations of two Timing Porks (M. P. I, Figs. 80li and 807 [830 and 831]), with two forks, two sliding weights, one cramp with glass plate, one style, two counterpoises and a rase for the tuning forks The apparatus consists of two very massive tall stands to which thr tuning forks ;uv fixed. One of the forks is movable on a sliding carriage. Both forks arc provided \\ith electromagnetic drive and carry steel mirrors. The forks are very massively constructed and are tuned to <•„ 1 L'S compound vi- brations (ut2 = 256 v. s). Tlie vibrations of the fork can lie placed parallel and perpendicular (o each other. A sooted f^lass plate and style can lie clumped on the forks. The curves obtained can lie projected direct. For obtaining different curves the forks listed on the next pai;c are employed. 8. d. 0.0 18. 0.0 * Can be used with the Projection Apparatus. Cl. 1108, 3377, 1142. 1141. No. 53 560. Tuning Fork Apparatus. Recording Tuning Forks. 455 53 553/58. 1 : 0. 53559. 1:10. Tuning Forks, Fi g u r e, for the preceding apparatuses for demonstrating the Lissajous Curves with various phase dif- ferences (M. P. I, Fig. 695 [719]), very large and massive pattern. (a) With Steel Mirror (b) With Glass Mirror Compd. Vib., ut3=512v. s. 53,545. Phase Difference 1 2, Cj = 256 53,546. 1 3, gt = 384 53,547. 2 3, g0 = 192 53,548. 3 4, f0 = 170V3 53,549. 3 5, a0 = 213V3 53,550. 4 5, e0 = 160 53,551. 5 6,a-,= 106V3 so!3 = 768 v. s. sol, = 384 v. s. £ 2. 8. 0 £ 2. 6. 0 £ 2. 12. 0 £ 2. 14. 0 £ 2. 10. 0 £ 2. 14. 0 £ 3. 0. 0 £ 2. £ 2. £ 2. £ 2. £ 2. £ 2. 2. 0 0.0 6. 0 8.0 4. 0 8.0 fa2 = 341V3 v. s. Ia2 = 4262/3 v. s. mi2 = 320 v. s. lat = 213V3 v. s. £ 3. 0. 0 £ 2. 14. 0 The Tuning Forks together, listed above, give, with fork c0 = 128 compound vibrations (ut2 = 256 v. s.) of Apparatuses Nos. 53,541 — 53,544, the phase differences indicated. If desired we supply suitable boxes for 2, 3, 4, 5, 6 and 7 forks at prices of £ 0. 14. 0, £ 0. 16. 0, £ 0. 18. 0, £ 1. 0. 0, £ 1. 2. 0 and £ 1. 4. 0. £ s d * 53,552. 7 Tuning Fork Curves on Stand, Figure, for the Projection Lantern 1. 0. 0 The curves are taken with Tuning Fork Apparatus No. 53,544 and show the phase differences 1 : 2, 2 : 3, 3:4, 3:5, 4:5, 5:6, and 35 : 36. Recording Tuning Forks, Drums and Vibrographs. Chronographic Tuning Forks for phonautographic purposes, Figure, with style and elec- troinagnetic drive, accurately adjusted at 20° C. List No. 53,553 53,554 53,555 53,556 53,557 53,558 Compd. Vib. per second 50 100 200 250 500 1000 V. s. 100 200 400 500 1000 2000 £ 5.0.0 4.0.0 4.0.0 4.0.0 4.0.0 4.10.0 53.559. Recording Device for Determining the Frequency of a Tuning Fork, for Students' Use, after Hahn, Figure, with pendulum, 1 tuning fork c1? 1 tuning fork dt, 3 glass plates, 1 blackening lump, 1 striking hammer (Hahn, Schiileriibungen, Fig. 152) 53.560. Stand for fixing Vibrating Bodies, Figure on p. 454, with tuning fork of 50 vi- brations and electric signal, to be used in conjunction with the cylinder of the Phonau- tograph (No. 53,571) 1. 10. 0 9. 0. 0 * Can be used with the Projection Apparatus. Cl. 1143, 339, 1167, 5967. 456 Acoustics. No. 53 561 — 53564. 1:11. 53 568. 1 : 7. 53 567. 1 = 7. 53.561. 2 Tuning Forks with Recording Device on Wood Stand, c0 = 128 compound vibrations £ s. d. (ut, = 256 v. s.), one fork fixed, the other movable and provided with sliders for gra- phically demonstrating the vibrations of two tuning forks (M. P. I, Figs. 806 and 807 i [830 and 831]) 6. 0. 0 By means of the sliders one fork can be altered in relation to the other by 4 : 5. 53.562. Forks for above with different number of vibrations Each 1. 10. 0 53.563. 2 Tuning Forks with Recording Device, large pattern, on Iron Stand, cf . Figure 53,564 i with two forks, c0=128 compound vibrations (ut2 = 256 v. s.) 10. 0. o 53.564. - - idem, with electromagnetic drive for both forks, Figure 13. 0. 0 53,56o. Forks for above, of different frequency Each 2. (i. <> 53.567. Vibrograph after Duhamel, Figure, for determining graphically the frequencies of tuning forks (Pisko, Die neueren Apparate der Akustik, Fig. 11) 3. 0. 0 53.568. Recording Drum with Clockwork, F i g u r e, can be used vertically and horizontally ; speed variable from 40 — 1/2 mm per second by friction; the drum can be moved along the axis and easily removed 6. 0. 0 53.569. — idem, wit-h electric contact »>. 1<>. i> 53.570. Phonautograph after Konig, with tuning fork stand, Figure (M. P. I, Fig. 668 [694]). Price without forks 11. 0. 0 The tuning forks to use are the chronographic forks with electromagnetic drive. \<>s. ~>3,553 — 53. .v.s Tne tuniiii; lurk curves can also be taken on sensitied paper and fixed permanently in accordance with Nimt'iilir's process (Drudes . \mialen der I'liysik. IV.. I'.ioii. Vol. 111. p. tiJTl. 53.571. Phonautographic Cylinder alone, on iron stand, sec Figure 53,570; without base- plate, tuning fork stand or tuning forks !t. n. (i 53,57'-'. Membrane Phonautograph after Scott and Konig (with comparison tuning forks). (Pisko, neuere Apparate Fig. 23) -'•">. A tmiinu lork of c, --'."Hi riini|miuid vibrations iul:, ~>\- V. %.) with style U placed in Iiout ol' the movable cylinder. liehind the fork is a parabolic Inline], do-ed with a membrane, t lie latter also Cl. 5515, 5357. 3379. No. 53575. Recording Tuning Forks, Phonautographs, Vibration Microscopes. 457 53570. 1:14. 53 575 A. 1:8. 53 574. 1 : 6. 53 575 B. 1 having a style. The vibrations of a tone acting on the membrane are recorded along with the curve £ s. d. of the fork having a known frequency, thus rendering it possible to determine the vibrations of a tone. Fortuning forks with other frequencies: see Nos. 53,553 — 53,558. 53,573. Phonautograph after Scott, without tuning forks (M. P. I, Fig. 804 [828]) .... 53,57-4. Vibration Microscope after von Helmholtz, Figure (Lissajous's Improved Com- parator), with a very massive tuning fork c0= 128 compound vibrations (ut2 = 256 v. s.), with electromagnetic drive for permanently maintaining the vibrations and with two sliders for varying the pitch (M. P. I, Fig. 701 [725]) 21. 0.0 7. 10.0 53,575. --idem, Figures A and B, with two stands and five massive tuning forks, each provided with objective, steel mirror and slider 33. 0. 0 All tuning forks are arranged for working with electromagnets; the two electromagnets and the forks can be adjusted; the eyepiece also is adjustable vertically and horizontally by micrometer Cl. 3380, 1170, 1169, 1171. 458 Acoustics. No. :>:if>76 — 53577 (53578). 1:8. 53583. 1:11. 53,576. Vibration Microscope, after Weinhold, Figure (W. D. Fig. 239 [225]); can be used at same time as a Topler Vibroscope .......... ........ * 53,577. 2 Massive Tuning Forks on Stand for the tone c0= 128 compound vibrations ut.2 = 256 v. s.); the pitch of one can be varied by filling with mercury; both with steel mirror and large resonator, Figure (Pogg. Ann. d. Phys. u. Chemie, Vol. 157, 1876, p. 621), for producing any phase differences and impact tones, also for Lissajous's Figures . . . One of the two tuning forks hat; both limbs bored out and is provided at the yoke with a screw press by means of which mercury can be forced into the limb. In this manner the frequency can bo altered by 8 compound vibrations ( = 16 v. s.). The resonator of each fork is provided with a i;ap which can he increased or decreased by means of a screw so as to suit its tone to that of the fork. The forks have electro magnetic drive. £ s. d. 6. 0.0 L'7. 10.0 .">:;, 57S. Variable Tuning Fork cc= 128 compound vibrations alone (iiU -•"•'• v- *•)• on stand and with variable resonator ........ «. . : .- u ' (l- ."i. •'..:> T'.i. 2 Tuning Forks with Resonators, same pattern as No. 53.577. but smaller, for i In- tone Cj = 256 compound vibrations (ut3 = 5l2 v. s.) 19. 5. (i 21. 0.0 .•>:•. :»so. Variable Tuning Fork GI = 25(> compound vibrations (ut3 = 512 v. s.), alone, on stand \\ilh variable resonator * Can be used with the Projection Apparatus 15. 10. 0 C'l. 1172. 5814, 1173, 3381. No. 53 585. Vibration Microscopes. Sound Analysis and Synthesis. 459 53 585. 1 = 7. 5.3,581. 2 Tuning Forks with Resonators, same pattern as No. 53,577, for tone ga = 192 com- I £ s. d. pound vibrations (so!2 = 384 v. s.) 25. 0.0 53,582. Variable Tuning Fork g0 = 192 compound vibrations (so!2 = 384 v. s.) alone, on stand and with variable resonator 53.583. Sound Analysis Apparatus after Konig, Figure, for fundamental tone c0 = 128 compound vibrations (ut., = 256 v. s.), with 8 spherical Resonators for tones c0, CD gx, c2, e2> 82* 7, c3 (ut2, ut3, so!3, ut4, mi4, so!4, 7, ut6), and 8 gas-flame manometers, on stand with rotating mirror (M. P. I, Fig. 822 [847]) 53,283. Reed Pipe with Sound Horn, Figure 53,282, p. 429, fitting above apparatus, for tone c0 = 128 compound vibrations (ut,=256 v. s.), very full tone 53.584. Sound Analysis Apparatus after Konig, larger, Figure, with arbitrary fundamental tone and 14 Universal Resonators (see No. 53,518), for the 46 tones g-j = 96 to e3 = 1280 compound vibrations (so^ = 192 to mi5 = 2560 v. s.) ; lowest arbitrary fundamental tones g_2 (sol_,) (Pogg. Ann. 146, p. 189) The apparatus is built into a massive frame and is provided with hand-driven rotating mirror the mechanism of which is so arranged as to run absolutely silently. The 14 Universal Resonators can be regulated in such manner that the highest tone of the larger always reaches the deepest tone of the smaller. They can therefore be set for any fundamental tone. The deepest arbitrary fundamental tone is g— „ = 48 compound vibrations (sol—! = 96 v. s.). The resonators are connected with manometric flames. The latter are protected from air currents by mica strips, which entirely obviate any breaking or spurting of the flame. For suitable Reed Pipe see No. 53,282, p. 429. 53,339. 14 Tuning Forks on Resonance Boxes, Figure 53,339 on p. 437, giving the first 14 overtones of c_, = 64 compound vibrations (ut] = 128 v. s.), for comparing with the resonators 53.585. Vowel Apparatus after von Helmholtz, with 8 harmonic tones, Figure, for de- monstrating sounds of different timbre, and more especially the vowels of the human voice (H. Helmholtz, Die Lehre von den Tonempfindungen, 4th Edn., Brunswick, 1877, pp. 194 et seq.) The apparatus consists of 8 tuning forks forming the first harmonic tones of the fundamental tone c0 (uts) and which are fixed between electromagnets. The electromagnets are traversed by a current rendered intermittent by an interrupting tuning fork making 128 compound vibrations (256 v. s.). Each tuning fork possesses a resonator which can be closed by a flap; the resonators can be opened more or less by means of a keyboard. When the resonators are closed the tuning forks are scarcely audible, but they sound immediately with the desired intensity when the corresponding keys on the keyboard are depressed. The interrupter circuit can be regulated by a resistance appended to the apparatus. The point of inter- ruption itself is provided with massive platinum contact. Each electromagnet can be cut out singly; by using corresponding additional resistance it is possible to obviate any variations in the current conditions. Cl. 1176. 18. 0.0 15. 0.0 1. 6.0 30. 0.0 17.10.0 60. 0. 0 460 Acoustics. No. 53 086 — 53 586. 1 : 8. 53 587 B. 1:4. 53588. 1:10. 53589. 1 : 10. 53.586. Vowel Apparatus after von Helinholtz, as No. 53,585, but larger, Figure, with £ s «'• 10 harmonic tones TO. o. <> 53.587. Telephone after Ph. Keis, consisting of transmitter (Fig. 53,587 A) and receiver (Fig. 53,587 B) 4.0.0 Between the transmitter and receiver — called by Reis himself tin- reproducing apparatus — a ' battery is so inserted that both are traversed in series by the current. The strength of the current should be such that the armature of the small magnet on the transmitter is attracted: .'i to 4 Bunscn cells or accumulators are sufficient for the purpose according to the distance lietwecn both stations. Further Telephones see Section "Electricity". 53.588. Large Edison Phonograph for Wax Cylinders, F i g 11 r e. with recorder and reproducer for speeches, musical selections, etc., with clockwork in base, with one recording and one reproducing membrane, and one sound horn 6. '_'. 0 Given in with the phonograph are 1 blank record anil 1 record with nm-ieal Delect ion. Tin- a;>p;ratus can be set into action without any previous knowledge or special skill, both for recording and reproducing -peeches. songs, etc. Tne reproclnel ion is so loud that it is possible to hear cuc'i uord plainly, even in sonirs. in a large room 10 x 10 m. Kadi cylinder can be used many hundreds of time-. Cl. 1177. 3fi71, 1178, 117(1, I.', U. No. 53 598. Vowel Apparatus. Phonographs, etc. Impact Tones. Interference of Sound. 461 53 592. 1 : 7. 53594. 1: 11. 53595. 1:11. 53 597. 1 : 5. 53.589. Small Edison Phonograph, similar in construction to preceding, Figure, with £ s. d. open clockwork, with one recording and one reproducing membrane, one sound horn, with oak containing case 3. 2. 0 53.590. Wax Cylinder, suitable for above phonographs, blank 0. 1. 0 53.591. - - i d e m, with music, speech or song 0. 1. 0 53.592. Gramophone with Clockwork, Figui e, for reproducing instrumental music, songs and speeches 6. 0. 0 53.593. Ebonite Disc, suitable for above Gramophone, with instrumental music, song or speech, as desired 0. 3. 0 Telegraphone after Paulson: see section on "Electricity". 53, 5! i4. Tone Impact Apparatus after Konig, Figure 20.- 0. 0 The apparatus has an iron frame upon which a wheel covered with cloth can move. Four clamps can be moved on two movable spring arms, these clamps taking glass tubes. These bars are clamped on the cloth covered wheel; and as soon as the wheel, whose lower part is immersed in water, is set into motion, impact tones of high intensity occur (Wied. Ann. 12, p. 351, 1881). 53.595. Sound Interference Tube, Figure (W. D. Figs. 253, 254 [239, 240]), of metal, with adjustable closing bows 1. 10. 0 The apparatus should be used with the exciter rod and the clamps of the Kundt Dust Figure Apparatus No. 53,315. If this apparatus is not available, No. 53,596 should be ordered. 53.596. - - idem, with Dust Figure Exciter Tube, for the tone a, = 435 compound vi- brations (Ia3 = 870 v. s.) 2. 5.0 53.597. - - idem, after Quincke, Figure, of glass with rubber tubing (M. P. I, Fig. 789 j [813]) 0. 5.0 53.598. — idem, after Norrcnberg (M. P. I, Fig. 788 [812]), of wood, for building into a wall 0. 18. 0 C'l. 1181, 5176, 1182, 554S. 462 Acoustics. No. 53599- 53599. 1:8. 53 600. 1 : 5. 53 601. 1 : 10. 53 602. 53 603, 53 339, 53 517, 53 298. 1:12. 53.599. Sound Interference Apparatus after Drenteln, Figure, consisting of two tuned glass resonators with three attachments, two india-rubber tubes each 35 cm long, and one ditto 70 cm long (Ztschr. £. d. phys. u. chem. U., 7, p. 273) The glass cylinder with blowing tube and small lamp No. 53,459 should be used in conjunction with this apparatus. 53.600. Sound Interference Apparatus with Tuning Fork and Receiver Membrane, F i g u r e, with two indiarubber tubes and drum-stick (Fr. phys. Techn. IT, 2, Fig. 3088) . . . 53.601. Apparatus for Comparing Two Tones of Pipes by Konig's Manometric Flame Method, Figure (Pogg. Ann. 146, l.STii, p. 166) The apparatus consists of a wind chest with two valves. ."> pipes (e,. c,. c,. g,, c., [ut.,. nt:). mi3, so!3, ut4]), 1 stand for 2 manometer flames and a rotating mirror on stand No. (il.4!in. 53.602. Fork-shaped Tube, F i g u re (M. P. I, Fig. 787 [811]), for demonstrating the inter- ference of sound waves by the aid of Chladni's Sound Figure Disc. I 'i ice without Sound Figure Disc s. d. 0. 6. 0 0. 18. 0 10. 0.0 li. 15.0 53,603. Sound Interference Apparatus after Konig, Figure, with (luce manometer flames and one small mirror (ef. I'ogg. Ann. 1872, Vol. 146, p. 195) II. 0. The apparatus consists of a stand uilh tulie. the latter being divided at the ends into two :inn-. one of which can lie lengthened at will, and a, stand with three <;a~ flame manometers. If the innermost gas flame i.; replaced by a small mirror the upper edge of which readies to half the height of the gas flame, rl. ;.860, 5741. 60291. 1184, 1185. Xn. :>3609. Sound Interference. Tuning Fork Clock. Phonic Wheel. Mechanical Effects. 463 53 605. 1 : 6. 53 604. 1 : 7. 53608. 1:5. and the eye is directed in such manner that the directly visible upper part of the one flame appears to form the direct continuation of the reflected lower part of the other flame, the image is not disturbed when the tubes of the apparatus are of the same length. If, however, the tube lengths are not equal, phase dif- ferences occur between the two flames and the two -visible halves will appear to be laterally displaced relatively to each other. Tuning fork, resonator and rotating mirror on base are not included in the price. 51,730. Spark Chronograph after v. Beetz, Figure 51,730, p. 249 53,604. Tuning Fork Clock after Maudet, Figure, with tuning fork making 64 compound vibrations (128 v. s.) (Koenig, Quelques experiences d'acoustique, p. 173) For very accurate determinations of the frequencies of standard forks by comparing the tuning fork clock with a standard clock at different temperatures. The fork is set into vibration and replaces the pendulum of the clock in that it regulates the motion of the clock by means of the escapement; the clock can be also used as a Vibration Microscope. £ s. d. 7. 10. 0 48. 0. 0 for accurately determining the frequencies 53.605. Phonic Wheel after La Cour, Figure, of tuning forks and for similar purposes A toothed armature with 20 teeth moves in front of the poles of a horse-shoe shaped multipolar electromagnet. The electromagnet is periodically excited by means of a tuning fork with electromagnetic drive, which opens and closes the circuit. The axis is provided with a counting mechanism which permits of the number of rotations being read off. Exhaustive information as to the manipulation and method of employing the Phonic Wheel may be found in the original work: ,,Das phonische Ead von Paul La Cour", published by Quandt and Handel, Leipsig, 1880. The phonic wheel can be driven with a fork making up to 128 compound vibrations (256 v. s.). 53.606. Tuning fork Jor above, c0 = 128 compound vibrations (ut2 = 256 v. s.), with electromagnetic drive for maintaining the vibrations Mechanical Effects of Sound. 53.607. Acoustic Apparatus after Dvorak (Ztschr. f. d. phys. u. chem. U., 6, p. 186), being a selection from the individual apparatus, Nos. 53,608—53,610 and 53,613 — 53,623, listed below The smaller apparatus are placed in a containing box. The Figure Nos. in brackets relate to Dvorak's article (loc. cit.). The experiments are very interesting. 53.608. Device for Acoustic Attraction and Repulsion, Figure (Fig. 1) 53,609. Device for Acoustic Attraction and Repulsion for Gases which are lighter than Air (Fig. 2) 7. 10. 0 4. 10. 0 5.17.0 0. 3.0 0. 3.6 Cl. 5206, 5760, 1195. 464 Acoustics. No. 53 610 — 53 610. 1 : 5. 53 612. 1 : 3. 53 615 an.l 53 617. I : '>. 53 619. 1 : 53.610. Acoustic Reaction Wheel, Figure (Fig. 5), tuned to the tone g, (so!3), with glass £ s. d. resonators, without glass vessel 0. (i. o 53.611. - - idem, tuned to gt (so!3), with spherical Aluminium Resonators 1. 0.0 53.612. - - id e m, tuned to c2 (ut4), Figure, consisting of 4 aluminium Resonators joined by a light aluminium cross-piece, on stand 1. 16. o A tuning fork c, (ut,) with resonance box is necessary for working this apparatus. 53.613. Resonator with 4 Apertures (Fig. 4) u. 7. n 53.614. Glass Cylinder for the Acoustic Reaction Wheel (Fig. 5) ' 0. l.o 53.615. Stand with Steel Pivot for setting up the rotating bodies, Figure, adjustable 0. 4.0 53.616. Reed Pipe (Fig. 7) 1. 4. o The horn without reed, No. 53,622, is inserted into the aperture of the same. 53.617. Small Paper Wheel (Wind Wheel), Figure (Fig. 8) 0. 2. 6 53.618. Glass Resonator, arranged to float (Fig. 3) 0. (i. o 53.619. Resonator for Tone g, (so!3) with stand, Figure (Fig. 8) 0. 10. 0 53.620. Massive Tuning Fork g, (so!3), with resonance box 1. -'. o 53,62.1. Sound Radiometer, consisting of four perforated sheets of paper fixed on a wood cross (Ztschr. f. Instrumentenkunde, 3, 1883, p. 130) . 0.6.0 53,284. Horn, with Reed, g, (so!8) (Fig. 6), see Figure 53,284, p. 429 0. -I. o 53.622. Horn without R*ed, g, (sol,) (p. 186 and Fig. 6) 0. 3. 0 53.623. Phonometer (of. Fig. 9), on stand and with tilting board 0. 12. o Cl. 1196.11U7. lliis. HOT. Xo. 53629. Optics. 465 53 624 A. 53 624 B. 53 624 C. /.: /X, 53626. 1:11. 53 629. 1 : 2. Optics. Propagation and Intensity of Light. 53.624. 1 Photometer Screen, Fig. A; 1 white screen with centimetre net, 1 screen with square centre-piece cut away, Fig. B ; 1 screen with 5 diaphragms for inserting, Fig. C; 2 dull white screens, of metal, with eyes for hanging and with 3 stands (M. T., p. 167 and Fig. 121) . 51,028. Projection Screen with Stand for raising and lowering (M. T., Fig. 122) 53.625. Sal-ammoniac Vapour Apparatus (M. T., Fig. 123) 53.626. Apparatus for Demonstrating the Rectilinear Propagation of Light, Figure (W. D., Fig. 260 [246]) The apparatus consists of a paper screen on metal stand, a large pasteboard diaphragm screen, and a stand (see above figure) with three small paraffin lamps, arranged triangularly. Measurement of the Velocity of Light after Fizeau and Foucault. Cf. Auxiliary Apparatus to Rosenberg's Universal Optical Apparatus No. 53,866. 53.627. Apparatus after Grimsehl for Determining the Ratio of the Velocity of Light in Air and Water (Phys. Ztschr. 7, 1906, p. 472, Fig. 1) 53.628. - - idem, for air and glass (Phys. Ztschr. 7, 1906, p. 473, Fig. 2) 53.629. Light -Angle -Measurer after Weber, Figure, for determining the luminosity of places (Ztschr. fiir Instrumentenkunde 4, 1884, p. 343), can be folded up .... This apparatus is used for measuring the angle from which the open sky is visible from the place being investigated, and the angle of elevation at which the light falls upon the place. £ s. d. 3. 0.0 0.16.0 0. 3.0 0. 16. 0 2. 5. 0 1.16.0 4. 10. 0 C'l. 5103, 5104, 1200, 1204. 5102, 30 466 Propagation and Intensity of Light. No. 53 630 — 53 630. 1 : 3. 53631. 1:5. 53 633. 1 : 6. 53 637. 1 = 4. 53 639. 1 : 8. 53.630. Aperture Goniometer after Gotschlich, F i g u r e, for the same purpose, giving simul- £ 8- d- taneously the upper and central angle of incidence 2.4.0 The apparatus consists of a stand with graduated arc in the centre of which are two rotary mirrors. The axes of rotation of the mirrors are indicated by engraved lines Two pointers are con- nected with the mirrors and show the predominating inclination on the graduated arc. By means of a spectacle-shaped sighting arrangement with fine ilirends a sight is taken of the mirror, which is adjusted in such manner that the engraved axis of the one mirror falls in a line with the upper edge of the window, while the axis of the other is made to coincide with the ridge of the opposite house. The portion of the arc situated between the two pointers is equal to half tin- angle of aperture. 53.631. Photometer after \Vingen, Figure, for directly determining the luminosity of workplaces in metric candles (range 10 — 50 metric candles) 2. 0.0 The area to be investigated is compared by observing with a red glass with a rotary surface inside the apparatus, this latter surface being illuminated by a small benzene lamp, the height of flame of which can be regulated. By rotating the comparison area relatively to this lamp, an external pointer is actuated, and permits the luminous value of the area investigated to be read off on a scale direct in metric candles. 53.632. Carrying Case for above, lock-up, with handle 0. 10. 0 Cl. 1205,5930, 59'.>9, 3«72, 1209. No. 53 644. Luminosity. Photometers. 467 53 640. 1 : 2,5. 53 643. 1 : 12. 53 644. 1 : 15. 53,633. Photometer after Wingen, for determining intrinsic brilliancy, Figure; benzene £ s d- lamp with optical flame measuring apparatus after Kriiss, for a range of 1 — 500 metric candles . 4. 0. 0 This photometer is constructed on the same principle as the preceding apparatus, hut admits of more accurate and extensive measurements. 53.634. - - idem, with Hefner Lamp 53.635. 3 Demonstration Photometers after Lambert (Eumford), Eitchie and Bunsen, modified by Kolbe (Ztschr. f. d. phys. u. chcm. U. 1, 1887 — 88, p. 193), without optical bench, together 53.636. Photometer Screen after Topler, on stand 53.637. Photometer after Bunsen, Figure (cf. W. u. E. phys. Prakt., p. 231, Fig. 130), with house, on stand The photometer corresponds to that used in practice. The grease-spot screen is enclosed, along with two tilted mirrors, in a sheet iron box open at both sides; to the side of this is the adjustable candle holder. 53.638. - - idem, with tape measure, for determining the distance of the source of light to be measured from the photometer 53.639. Photometer after Bunsen, Figure, with divided circle and rotary photometer house, to enable measurements to be made upon light sources from various angles . 53.640. Standard Photometer Bench, Figure, for testing gas flames, with two graduations, which give the candle power direct, with Photometer Head after Bunsen, cf. No. 53,637 The bench is constructed of iron and is 2,50 m long; the one graduation enables readings to be taken when the distance between Hefner lamp and photometer screen is invariable, i. e. when the lamp is on the carriage; the other graduation corresponds to the case of botli luminous sources per- manently set up on the ends of the bench. 53,641. - - idem, Equality . . with Lumner-Brodhun Photometer Head, cf. No. 53,653, for setting at 53.642. --idem, for setting at Equality and Contrast; for the most accurate measurements 53.643. Photometer after Eumford (W. D., Fig. 261 [247]), Figure, with 2 rules . . . 53.644. Photometer after Bouguer, Figure, foi measuring luminous intensity by com- paring two adjacent illuminated surfaces, with 2 rules 1. 4. 0 Regarding Apparatus for Testing Illuminating Gas for its sulphuretted -hydrogen content (also self-recording), its ammonia and carbonmonoxide and for testing the specific gravity, etc., kindly ask for quotations. Cl. 6040, 5999, 6034. 30* 10.10.0 3. 5.0 0. 12. 0 1. 10. 0 1.16.0 3. 0.0 10. 10. 0 15. 10. 0 17. 0.0 0. 10. 0 468 Propagation and Intensity of Light. No. 53 645 — 53646. 1 : 10. 53 647. 1 : 5. 53 649. 1 : 4. 53 650. 1 : 2. 53 651. 1 : 2. 53.645. Photometer after Foucault, Figure (Chwolson II, Fig. 350), with observing tube In this photometer the screen is formed by a glass plate covered with dry milk, this arrange- ment being very sensitive. 53.646. Photometer after Ritchie, Figure (Fr. phys. Techn. II, 2, Fig. 3379 [II, Fig. 693]) In this apparatus observations are taken on two white surfaces inclined towards each other. £ s. d. 2. 8.0 1. 4.0 53.647. Demonstration Photometer after Eitchie-Weinhold, arranged for objective demon- stration, Figure (W. D., Fig. 263 [249]) | 1. 2. 0 53.648. Diffusion Photometer after Joly, Figure (W. u. E. phys. Prakt,, Fig. 131) . . 2. 0. 0 The photometer consists of a screen, carrying in front of an aperture two small paraffin blocks with the plane surfaces pressed on each other. The paraffin blocks appear equally bright when illuminated to the same intensity and the partition joint disappears entirely. Absorption glasses run be inserted at M. 53.649. Photometer after Wheatstone, Figure (Gan.-Eein., Figs. 484 [485]) 1. 16. 0 The apparatus consists of a spherical mirror moved in a curve by means of a set of wheels. The luminous sources to be compared are reflected in the small mirror as two luminous points, which shine as two curviform image* of different brilliancy when the mirror is rotated and when the illu- mination is unequal. I 'I. 1212,1213, 1210, I'.Ml, 1214. 5931, 5932. No. 53 655. Photometers. 469 53 652. 1 : 2. 53 653. 2 : 5. 53 654. 1 : 9. 53 655. 1 : 14. 53.650. Flicker Photometer Head, Figure, with sector disc The Flicker Photometer is based on the fact that two illuminated surfaces coming alternately before the eye only show a flickering if differently illuminated. 53.651. -- idem, with rotating flicker body, Figure, with inclining device and degree graduation, for measurements from different directions 53,652. Lummer-Brodhun Photometer Head, mentenkunde 9, 1899, p. 41) with stand, Figure (Ztschr. fiir Instru- 53.653. - - idem, for viewing perpendicular to the luminous sources, Figure . . . . 53.654. Photometer after Leonh. Weber, Figure, with complete accessories, in polished wood box The photometer is based on the comparison of two illuminated ground discs, one of which is arranged so as to be movable in a horizontal tube; the tube perpendicular to the latter tube, and containing the other ground disc, contains a Lummer-Brodhun Cube, is arranged to rotate, and can be conveniently focussed on the luminous source to be investigated. A graduated arc permits the angle described to be read off. As comparison light source use is made of a small benzine lamp having a flame-height of 20 mm; the correct height can be read off on a scale pasted on plate glass, and can be adjusted by a rack. 53.655. Photometer after Eousseau, Figure, for photometering arc lamps in various directions (Elektrot. Ztschr. 8, 1887, p. 356) Cl. 1216, 3385, 5442, 1219. £ s. d. 5. 0.0 6. 15. 0 5. 0.0 6. 5.0 20. 0.0 9. 0.0 470 Propagation and Intensity of Light. No. 5365(5 — 53657. 1:16. 53.656. Glow Lamp Photometer, Figure, with comparison apparatus on Joly's principle, £ »• d. which permits of very sharp focussing 7. 10. 0 The photometer is 1 m long and is arranged in such manner that the candle powers of glow- lamps can be compared without a dark room, the ratio of intensity being read direct on a scale. The range extends in" both directions from 1 to 10 times. The exchange of the glow lamps under test proceeds very rapidly. Calibrated glow lamps are used as standards. The apparatus is fitted with Edison Glow lamps sockets, but can be arranged for any other holder. Comparison Glow Lamps — see Nos. 53,660 — 53,662. 53.657. Large Photometer Bench, 3 m long, Figure, with millimetre graduation, 3 Stands on Carriage, fitted with Lummer-Brodhun Photometer Head, Hefner Lamp, Candle Holder, Lamp Table, Photometry Stand for glow lamps and a Mirror for determining the luminous intensity of arc lamps at various angles of emission 34. 0. 0 The photometer bench should be placed on a table of suitable height so that the graduations can be conveniently read off: see also No. 53,659. 53.658. Angle Mirror for photometering glow lamps in accordance with the Rules of the Verband Deutscher Elektrotechniker 1. Hi. n 53.659. Portable Iron Table for the large Photometer Bench No. 53,657, with Rotary Switch- board and Regulating Resistance, Figure. Price exclusive of measuring instruments, regulating resistance, and photometer bench 17. 0. 0 The switchboard carries 1 voltmeter, 1 ammeter, and 1 wattmeter, also the requisite plug- contacts. The regulating resistance can also be manipulated from the farthest end of the bench. The prices of the measuring instruments and regulating resistance vary according to local current and voltage conditions, as to which we should require precise details. This table used in conjunction with photometer Bench No. 53,657 is intended for testing the luminous intensity of glow lamps in factories and electricity works. 53;660. Glow Lamp for use as Comparison Lamp, of appmx. 5, 8, 10, 16, 25, and 32 Candles (Hefner), specially for photometering glow lamps with Apparatus No. 53,656, for an accurately prescribed voltage 0. 5. 0 These comparison glow lamps are supplied calibrated at an accurately prescibed voltage and for a luminous intensity in one direction, approximately as ordered, e. g. for 16.6 Standard Candles (Hefner) at 110 volts. The lamps are supplied for the usual voltage-: when ordering the Voltage available and desired candle-power should be stated; in every case only one of these two values can be strictly adhered to. Zinc-Bulb Photometer for Determining the ultra-viole Radiation of the Sun quoted for on application. C'l. 6039, 1217. NIL r.3668. Photometers. Hefner Lamp. 471 53 659, 53 657. 1 : 23. 53 668. 1 : 2. It is advisable always to obtain 2 comparison lamps of the same sort, keeping one as a chief standard, i £ and comparing it from time to time with the standard in use. 53.661. - - idem, calibrated for an accurately prescribed Candle-power in one direction, for working on the photometer bench If accurate measurements are desired with these glow lamps -- especially in the photometry of arc light — the voltage obtained for the candle-power in question when calibrated must be adhered to. 53.662. - - idem, calibrated for an accurately prescribed mean horizontal Candle-power, for glow lamp measurements, in accordance with the rules of the Verband Deutscher Elektrotechniker, on Photometer Bench No. 53,657 and with the aid of the Angle Mirror No. 53,658 53.663. Hefner Lamp, admitted for test by the Physikalisch-Technische Eeichsanstalt (Ztschr. fur Instrumentenkunde, 13, p. 257), with optical flame measuring apparatus (after Kriiss), check gauge and scissors 53.664. - - idem, verified 53.665. - - with flame meter after v. Hefner- Alteneck, check gauge and scissors s. a. 0. 5.0 0. 7.0 2. 2.0 2. 6.0 2. 2.0 53.666. - - i d e m, verified I 2. 6. 0 53.667. - - with 2 flame measuring apparatus, check gauge and scissors, cf. Fig. 53,668 . 2. 10. 0 53.668. - - i d e m, verified, Figure 2. 16. 0 Cl. 4500, 1221. 472 Propagation and Intensity of Light. No. 536«9 - 53 676 A, 53 678 (53 683). 1 : 20. L L 53 676 B. 1 : 20. 53,669. Spare Wick Tube for the Hefner Lamp, verified * 53.671. 6 Standard Candles 53.672. Optical Bench after Weinhold, cf. Figure 53,675 (W. D., 2nd Edn., Fig. 237), constructed in one part of wood, 4 m long, with scale on both sides and with 3 saddle- stands; in addition to being used as a photometer bench it can be employed for a large number of optical experiments. Price, without photometer screen, paraffin burner or comparison lamp For accessories: see Nos. 53,678 — 53,695. 53.673. --idem, of wood and constructed in two parts 53.674. - - i d e m, 3 m long, of wood and in one part, cf. Figure 53,675, without acces- sories . £ 8. <1. 0. 4.0 0. 3.0 53,675. - - idem, constructed in two parts, 3 m long, No. 53,684 illustrated Figure, without accessories 53.676. Optical Bench after Weinhold, entirely of metal, graduation 4 m long, and constructed in two parts, Figures A and B (W. D., Fig. 262 [248]), without the comparison lamps set up on the saddle-stands and without photometer Fig. A shows only one-half of the bench. 53.677. - - idem, graduation 3 m long, entirely of metal and constructed in two parts, cf. Figure 53,676 B 53.678. Photometrical Accessories with electric light, for the Weinhold Optical Benches, with Bunson Photo- meter, see Fig. 53,076 A and 53,678 a and b ; (a) Carrier with 4 tubular glow lamps and movable diaphragmic screen (£ 1.4.0); (b) 1 Com- parison Glow Lamp together with connecting leads and double plug-contact, arranged for inserting in the saddle-stands of the optical bench (£ 0.10.0); (c) 1 Bunsen Photometi-i . No. 53,683 (£ 1.2.0). 53.679. — idem, with Topler Photometer Screen No. 53,680 instead of the Bunsen Photometer. SIT Fig. 53,675 53.680. Photometer Screen (after Topler) alone, for inserting in the saddle-stands of ihr ITIU-II. MT l-'ig. 53,675 53.681. Photometrical Accessories for Gas Light, for Weinhold Photometer and Optical Hem-hes, see Fig. 53,681b and c, with Topler Photometer Screen (see Fig. 53,675), without stands (a) Incandescent Gas Burner (£ 0. 5. 0); (b) Carrier with 4 small gas jets and movable Diapin aizm (Fig. 53,681 b) (£ 0.12.0); (C) Small Comparison Lamp for gas (Fig. 53,681 c) (£ 0.3.0); (d) Topler Photometer Screen (see Fig. 53,675) (£ 0. 6. 0). 53.682. — idem, with Bunsen Photometer (see Fig. 53,676 A) instead of the Topler Photometer Screen . 53.683. Bunsen Photometer Head, alone, for inserting in the saddle-stands, of the brnrh (see Fig. 53.67UA) 3. 0. 0 3.12. 0 2. 10. 0 3. 2.0 4. 16.0 4. 10. 0 •2. 16. i> •_>. II. O (I. 6. 0 1. 6. 0 •-'. L'. II 1. 2. 0 Cl. 3674, 1223. Xn. 53698. Optical Benches. 473 53 678 a, 53 678 b, 53686. 1: 8. 53 689, 53 684a (53688). 1: 7. 53 684 b. 1:4. 53690. 1:5. 53681b, 53686. 1: 7. 53 681 c, 53686. 1:7. 53.684. Photometric Accessories with paraffin light for the Weinhold Photometer and Optical Benches, of. £ s. d. Fig. 53,675, with Topler Photometer Screen, without stands 1. 7. 0 (a) Paraffin Lamp, Figure (£ 0. 6. 0); (b) Carrier with 4 small Paraffin Lamps and movable diaphragm, Figure (£ 0.12.0); (c) Carrier with small Paraffin Comparison Lamp (£ 0.3.0); (d) Topler Photometer Screen, see Fig. 53,675 (£ 0. 6. 0). 53.685. — idem, with Bunsen Photometer No. 53,683 instead of Topler Photometer Screen 2. 3. 0 53.686. Stands for preceding Accessories in order to enable them to be used independently on the lecture table in conjunction with any photometer (see pp. 467, 468) or to enable the accessories to be more conve- niently stored, see Figures Each 0. 5. 0 Three or four at least should be ordered. 53.687. Glow Lamp for 110 volts, with socket and haft, for concave mirror and lens experiments (W. D., p. 356 [329]) 0. 5. 0 53.688. Perforated Cylinder for concave mirror and lens experiments (W. D., Fig. 272 [258]), fitting Argand Gas Burner No. 53,681 a 0. 1. 6 53.689. — idem, for the Paraffin Burner No. 53,684 a, Figure, without burner 0. 1. 6 53.690. Diaphragmic Cylinder, Figure, with 5 diaphragms of different sizes, for Gas Lamps 0. 12. 0 The cylinder is 48 mm diameter. The diaphragm apertures are 0,5, 4, 10, 15 and 30 mm. 53,<>91. — idem, for Paraffin Lamps 0. 12. 0 .-,:;. ii<»2. 2 Screens for Concave Mirror and Lens Images (W. D., Fig. 273 [259]) 0. 8. 0 53.693. 4 Lenses in brass mounts with haft, 3 bi-convex, 1 bi-concave, for demonstrating the terrestrial, astronomical and Galilean Telescope and the Microscope 0. 16. 0 53.694. Convex Lens, exact focus 600 mm, 60 mm diameter, in mount with haft 0. 12. 0 53.695. Lens Holder with Haft, for inserting one or two lenses for investigating the focal length of a lense system, fitting Lenses No. 53,894 (W. D., p. 386 [354]) 0. 5. 0 53.696. Optical Bench after Friedr. C. G. Miiller (M. T., Fig. 114 and pp. 166 to 171, 173, 174, 175), 3 m long, with 4 saddle-stands 1. 10. 0 For screen for above, see No. 53,624. 53.697. Punctiform Limelight after Friedr. C. G. Miiller, for feeding with a gas blast burner (M. T., Fig. 115) 0. 6. 0 53.698. Arc Light after Friedr. C. G. Miiller (M. T., Fig. 116) 0. 6. 0 Cl. 6022, 3674, 1227, 1224, 1228, 1225. 1226. 474 Reflection of Light. No. 53699- o 53 707. 1 : 4. 537P3. 1:10. 53708. 1:8. 53709. 1:3. 53,699. Rectangular Platinum Wire Glow-Light (M. T., Fig. 117), serving as luminous source £ s. d. for concave mirror and lens images 0. 8. 0 53,70.1. Candle Holder for 5 Candles, with stand with height adjustment (M. T., Fig. 118) 0. 6. 0 53.702. Storing Box for the preceding luminous sources and the screens of No. 53,624 . . 0. 6. 0 53.703. Incandescent Gas Lamp, Figure, adjustable, with 5 diaphragms (M. T., Fig. 119) 1. 6.0 53.704. Arc Light Lantern (M. T., Fig. 120) 1. 4. 0 53.705. Prism, Disc and Cylinder of Cardboard, for showing the dependence of the luminous intensity on the angle of incidence and for photometric experiments (M. T., Figs. 125 [126]) 0. 4.0 53.706. Photometer Screen with grease spot for Fried r. C. G. Miiller's optical bench (M. T., p. 175), cf. Figure 53,624 A, without stand 0.10.0 Reflection of Light. 53.707. Apparatus for Explaining the Laws of Reflection, after Weinhold, Figure (\V. V. d. B., Fig. 245) 0.14.0 53.708. — idem, after J. Miiller, Figure (M. P., 9th Edn., II, 1, Fig. 27; Fr. phys. Teclm. II, 2, Fig. 2019 [II, Fig. 700]) 1. 0. 0 53.709. Apparatus for Explaining the Laws of Reflection, after Tyndall, F i g u r »•, varied by Prof. Mciit/ncr 1. 2. 0 The scale of the apparatus moves of itself so as to make its zero point agree with the incident ray of light. The apparatus can be used without darkening the room. 53.710. Reflection Apparatus after Stahlberg, Figure (Ztschr. f. d. phys. u. cliein. I'. 15, p. 73), on adjustable stand with foot-screw • • • 1. 8. 0 The hinge-pin of two metal bars carries a mirror and. perpendicular to ihc latter, a rod which always forms the angle-bisector for the two bars and thus forms the axis of incidence. The luminous ray along the one limb encounters the mirror and is always reflected along the other limb. The apparatus can be employed for light falling from the right or (lie left. For further apparatus for Reflection of Light: see Section "Light Helraction". d. 'ilin. r.oii. 123(1, 1231. No. 53741. Reflection of Light. 475 0 53 737. 1 : 5. 53710. 1:10. 53 740. 1 : 5. 53.711. Reflection Apparatus after Eosenberg (Kleiber, Gymnas., Fig. 206), for showing that £ s. d. the reflected rays of a punctifoim source of light appear to proceed from a point situated on the rear elongation of all the rays 1. 4. 0 53.712. Reflection Apparatus after Friedr. C. G. Miiller (M. T., Fig. 127), for showing that the reflected ray lies in one plane with the incident ray and with the axis of incidence 0. 18. 0 53.713. Polemoscope (Magic Mirror) (M. T., Fig. 128) . 0. 14. 0 53.714. Mirror Arrangement after Porro (M. T., Fig. 129), for reversing an image .... 0. 16. 0 Reflecting Prisms (Reversing Prisms), with round base surfaces, of Crown Glass, strictly accurate at all angles, without pyramidal error: List No. 53,715 53,716 53,717 53,718 53,719 Aperture of polished ) 07 „. ._ „ . base-surface mm ? 47 £ 1.17.0 2.9.0 3.0.0 4.3.0 5.15.0 List No. 53,721 53,722 53,723 53,724 53,725 Aperture of polished J base-surface mm j £ 9.15.0 14.10.0 17.5.0 28.15.0 46.0.0 - i d e m, sharp-edged, with polished base surfaces : List No. 53,726 53,727 53,728 53,729 53,730 Base-length mm 14 20 27 34 41 £ 0.18.6 1.10.0 2.2.0 3.12.0 4.18.0 List No. 53,732 53,733 53,734 53,735 53,736 Base-length mm 54 61 68 75 81 £ 7.0.0 9.5.0 12.15.0 17.5.0 23.0.0 Intermediate sizes are the same price as the next largest size. The height of prisms is equal to the length of the base. 53,737. Angle Mirrors, Figure, with a fixed mirror and a mirror movable in an easilv visible stav 53,720 61 7. 10. 0 53,731 47 5. 15. 0 the preceding hinges over 0. 16. 0 1. 12. 0 0. 8.0 1. 4.0 0. 12.0 1234 a, 53,738. — i d e m, of brass, on stand, Figure, with graduated arc . . . 53,739. — idem, without base and without graduation (M T , p 176) . . 53,740. Angle Mirror and Parallel Mirror, Figure, with two fixed double-sided mirrors 53,741 Parallel Mirrors after Friedr C G Miiller (M T pp 176 and 177) . Angle Mirrors for Geissler Tubes: C'l. 6036, 6038, 3386. 476 Reflection of Light. No. 53742 — 53 747. 1 : 7. 53 750. 1 : 3. Kaleidoscopes, with movable front part, simple construction, on wood stand: List No. 53,743 53,744 Diameter of Image mm 65 80 £ 0. 5. 0 0. 10. 0 53,745. - - idem, good pattern, on stand * 53,746. Projection Kaleidoscope on stand, Figure, giving very pretty images 53.747. Kaleidoscope for polarised light, Figure, with dark minor. Ts'icol prism, and gypsum objects ". 53.748. Conical Mirror, Figure, with 6 images (anamorphoses) 53.749. Cylindrical Mirror, Figure, with 6 images (anamorphoses) 53.750. Parabolic and Cylindrical Mirror after Rebenstorff, F i g u r e, with indication of the path of rays for parallcly striking rays, for demonstrating reflection and the caustic line, with a template according to which the curvatures are produced * Can be used with the Projection Apparatus. ri. 1268, 1266. 4515, 510!). £ s. ,1. L>. 0. O 1.10.0 3. (>. o (). in. (i 0. 10. 0 0. If,. ()• 1207, No. 53 778. Kaleidoscopes. Concave Mirrors. Covex Mirrors. 477 53752. 1:10. 53753. 1 : 10. 53 757. 1 : 6. 53775. 1:6. 53.751. Parabolic and Circular Mirror Ring for Demonstrating Catacautery, after Friedr. C. G. Miiller (M. T., Fig. 130) 53.752. Model of a Concave Mirror after Muhlenbein, Figure, with fixed and movable coloured rods for demonstrating the path of the rays and the relations between object and image 53.753. Model of a Convex Mirror after Muhlenbein, Figure Spherical Concave Mirrors and Convex Mirrors, of Glass, of exactly 600 mm focal length, Figure 53,757, ground optically true and silvered, in metal mount with haft and cover, without stand, for use on the optical bench, for demonstrating the images and laws relative to concave mirrors. Concave Mirrors silvered on front Convex Mirrors silvered on back Concave and Convex Mirrors silvered concave side Stand List No. Diam. mm Each £ s. d. List No. D»- Each £ s. d. ^oj ^ £Ef d. List No. Each £ s. d. 53754 53755 53756 53757 60 90 120 150 0. 12. 0 0.18.0 1. 4.0 1. 16. 0 53758 60 53 759 90 53 760 120 53 761 1 150 0.12.0 53762 60 0.18.0 0.18. 0 53763 90 1. 4.0 1. 4.0 53764 120 1.10.0 1.16.0 53 765 i 150 |2. 6.0 53766 0.5.0 The Concave and Convex Mirrors Nos. a cover both back and front. 53,762 — 53,765 consist of a single mirror provided with We supply Mirrors Nos. 53,754/57 and 53,762/65 also with an extra coat of gold for increasing the durability; extra price for this £ 0.3.0. Spherical Concave Mirrors and Convex Mirrors of Glass, cf. Figure 53,775, in black polished Wood Mount, with wood handle (M. T., p. 177). Convex Mirrors Concave & Convex Mirrors 53,769 53,770 53,771 53,772 100 150 100 150 350 350 350 350 0.4.0 0.7.0 0.6.0 0.10.0 List No. Diameter mm Focal Length mm Each £ Concave Mirrors 53,767 53,768 100 150 350 350 0. 4. 0 0. 7. 0 - i d e m, on Stand, Figure 53,775. List No. Diameter mm Focal Length mm Each £ Concave Mirrors 53,773 53,774 100 150 350 350 0. 10. 0 0. 13. 0 Convex Mirrors 53,775 53,776 100 150 350 350 0. 10. 0 0. 13. 0 Concave & Convex Mirrors 53,777 53,778 100' 150 350 350 0. 12. 0 0. 16. 0 £ s. d. 0. 12. 0 1. 2.0 1. 2.0 CI. 6043. 6042, 1235, 1236. 478 Reflection of Light. No. 53779 — 53779. 1:8. 53 795. 1 : 6. 53,779. Spherical Concave Mirror, of glass, with small box, bouquet and vase, for producing real images, Figure In a black box is arranged, inverted, a bouquet, which has to be strongly illuminated. By means of a concave mirror an upright, real image is produced of this bouquet, this image appearing to issue from the glass when the correct position is given to the rotary mirror and on glancing, a suitable distance off, at the glass and the mirror. Spherical Concave Mirrors, of Glass, ground, fixed on Stand, silvered on the back, focal length 600 mm. List No. 53,789 53,790 53,791 53,792 Diameter mm 200 300 400 500 Each £ 3. 0. 0 4. 0. 0 6. 0. 0 9. 0. 0 Style: as Nos. 53,780/84. 53,794. Spherical Mirror (M. T., p. 177), 100 mm diameter, on stand 53.795. Japanese Mirror (Magic Mirror), Figure, of metal, with force-pump The images can be rendered visible both by sunlight and with the projection lantern. 53.796. Glow Lamp Ring after Grimsehl, for concave minor experiments (Fr. phys. Tcehn. II, 2, Fig. 2648), stand with 16 7-volt electric glow lamps in scries 53.797. Black Mirror, for drawing, in case, 11 cm long, 8 cm wide 53.798. - - idem, 16 cm long, 13 cm wide 53.799. Plane Mirror, of silvered glass, in frame t: s. d. 4. 10. 0 0. 10. 0 5. Hi. (i 2. 1.0 (I. 10.0 0. 18. 0 0. 4.0 Mirrors of perfectly plane parallel glass, coaled with silvei. for instruments read by a mirror. List No. 53800 53,801 53,802 Thickness mm 0.5—1 0.5—1 0.5—1 Diameter mm 5—10 11—15 16—20 Kaeh t 0. 4. 0 0. 7. 0 0. 10. 0 Concave Mirrors for instruments with mirror-reading, silvered on back; focal length 100 cm. List No. 53,803 53,804 53,805 Diameter mm 10 !."> 2(1 Each £ 0. 6. 0 0. 9. 0 0. 12. 0 C.'l. 1237, 123'J. No. 53 809. Concave Mirrors. Plane Mirrors. 479 53 806. 1 : 8. 53 807. 1 : 7. 53809,53806. 1:6. 53.806. Demonstration Goniometer after Weinhold, of. F i g u r e, large Pattern (W. D., I £ s. d. Figs. 265—267 and 286—288 [251—253 and 270—271]) 118. 0. 0 The Goniometer can be used horizontally and vertically. It is used for more accurate experiments on reflection, refraction and colour-dissipation, for determining the angles of prisms and refractive indices by Fraunhofer's, Meyerstein's or Listing-Abbe's Method, as a Goniometer and Spectrum Appa- ratus. Height, 50 cm; diameter of circle, 55 cm. The apparatus is graduated in whole degrees. The accessories comprise a centering plate for crystals, a plane mirror in mount, a water-vessel with gap, a gap with illuminating mirror, one index, two lenses, one collimator tube, one observing telescope, one prism of flint glass, 45 mm side, and a key. All parts placed in a box. 53.807. - - i d e m, with a second graduation on brass in whole degrees and with vernier reading, for subjective observations, Figure 21. 0. 0 53.808. - - the same apparatus as No. 53,806, but without Telescopes, without prism or box; cannot be used as a Spectrometer, etc 15. 0. 0 53.809. Ocular with Gap for the observation telescope, and Symmetrical Double Gap after Vierordt (v. Konkoly, Handbuch der Spektroskopiker, Halle, 1890, pp. 388 — 390), for the collimator tube 'of the Weinhold Goniometer No. 53,806 or 53,807 (cf. F i g. 53,809), in order to enable the apparatus to be used in addition as a Spectrophotometer . . i 7. 10. 0 Ocular and double gap can be set up forthwith on the observation telescope or collimator tele- scope supplied with NOB. 53,806 or 53,807. The illustration shows the demonstration goniometer arranged in the manner in which it is used as a Spectrophotometer. Cl. 6057, 5317, 3076. 480 Reflection of Light. No. 53810 — 53 810 A. 1:7. 53 810 B. 1:7. 53 814 A. 1:5. 53 814 B. 1:6. 53,810. Demonstration Goniometer after Weinhold, small pattern, cf. Figures A and B The Goniometer is used as No. 53,806. apparatus is divided in whole degrees. Accessories as No. 53,806. The height is 13 cm, diameter of circle 38 cm. The 53,811. - - idem, with a second graduation on brass, in half degrees, and with vernier reading, 14. S. (1. 0.0 for subjective observations 53.812. - - the same apparatus as No. 53,810, but without telescopes, prism or box . . . 53.813. Simple Goniometer for students' use, after Noack (Noaek, Leitfaden t'iir Schiiler- iibungen, p. 9), for use with accessories No. 53,815 — 53,817 and 51,851 1; can be used as a Demonstration Goniometer for subjective and objective observation, as a Spec- trum Apparatus and for various other optical experiments; as a Magnetometer, Galvano- meter, and Tangent Galvanometer; for Demonstrating the Parallelogram of Forces, the Reflection of Impact and of Torsional Effects .~>.'5,814. Demonstration Goniometer after Noack, Figures A and B (/tschr. f. d. phys. u. chem. U. 3, 1889—90, pp. 1 and 57) The divided circle of zinc, with German silver edge, is very accurately graduated in half-degrees and permits of readings being made to 5 minutes with the aid of the vernier provided on the 3 alidades Cl. 3942, 3941. 1250, Ii55. 16. 11. (I. (I 10. 0 15. 0.0 0.0 No. 53821. Demonstration Goniometer. Reflecting Goniometers. 481 53 819. 1 : 3. 53 820. 1 : 3. pertaining to the apparatus. Hollow brass pillars can be screwed into the alidades, and various acces- sories can be fitted into the pillars, e. g., for optical experiments, two massive brass forks with lateral levelling screws and two brass heads pointed at the top, and these accessories are interchangeable. The following are supplied along with the apparatus: 4 small pillars, 4 cylinders, 1 movable table top, 1 key, 2 brass forks, 2 brass pivots, 1 gas burner, 1 glow light and 1 camera obscura. 53.815. Accessories for Optical Experiments for the Noack Goniometer (a) Telescope (£ 1.10.0); (b) Slotted Tube (£ 1.10.0). 53.816. Accessories for Magnetic and Electric Experiments with the Noack Goniometer, Nos. 53,813 and 53,814 (a) Magnetometer with bar magnet (£ 2.14.0); (b) Compass with Binnacle (£ 1.16.0); (c) Gal- vanometer (without compass, £ 3.12.0); (d) Tangent Galvanometer (£ 1.0.0). 53.817. Accessories for Demonstrations in Mechanics with Goniometers Nos. 53,813 and 53,814 (a) 3 Pulleys, Fig. 53,814 B (£ 0.15.0); (b) Cubical Tube with Sphere (£ 0.5.0); (c) Ring for Tissue Paper (£ 6.6.0); (d) Torsion Head (£ 0.12.0). 51,85l'. Set of Weights, comprising 20 weights of 50 g each, with small hooks 53.818. Goniometer and Spectrum Apparatus for Students' Exercises, after Grimsehl (Ztschr. f. d. phys. u. chem. U. 17, 1904, p. 207) 53.819. Reflecting Goniometer after Wollaston, Figure, with telescope: the crystals are centered by a centering needle The divided circle is graduated in half degrees, of brass, silvered, and provided with vernier for reading to 2 minutes. The telescope aperture is 15 mm, the focal length 104 mm, and the power, 4. 53.820. --idem, Fig. 53,820, with Fine Motion and Magnifier reading The divided circle is 108 mm diameter, the fine motion being secured by worm and rack; with round pattern spirit level. 53,821. - - idem, simple, for students' use (Wied. u. Ebert, Fig. 135) On tripod with levelling screws, graduated in 1/,Q, vernier read by magnifying glass up to minute. £-3 s. d. 3. 0.0 9. 2.0 1. 18. 0 0. 10. 0 2. 8.0 9. 0.0 12.10.0 6. 0.0 Cl. 1243, 1244. 31 482 Reflection of Light. No. 53822 — 53 823. 1 : 6. 53826. 1:5. 53 827. 1 : 5. 50. 0. 0 53 822. Large Reflecting Goniometer with circle 230 mm diameter, with concealed graduation £• »• on silver, objective aperture 31 mm, reading by magnifying glass with 2 verniers for 10 seconds, with Centering Apparatus The circle and observing telescope have independent motion about the central axis, with screw motion. The measurements can be taken either by firmly clamping the circle carrying the crystal, and by turning the alidade along with the telescope, or by clamping the alidade with the telescope and rotating the circle with the crystal. The instrument has two oculars and a number of slots for the collimator; the observing telescope is provided with an extra objective, thus facilitating the focussing of the objects under test. Illustration on application. 53.823. Reflecting Goniometer, can also be used as a Spectroscope, K i g u r e, with circle 150 mm diameter, concealed, on silver, with reading by means of magnifying glass to 20 seconds; objective aperture 27 mm. Without Centering Apparatus 53.824. Reflecting Goniometer for the Laboratory, with circle 150 mm diameter, graduated | in l/3°, with telescope having an objective aperture of 22 mm, with magnifying glass, reading to 30 seconds. Without Centering Apparatus 27.10.0 53,825. Centering Device for the crystals, fitting the two preceding goniometers 19.0. i) 3. in. o 53.826. Reflecting Goniometer, smaller, without magnifying glass reading. Fig. 53,826, prac- tical model for laboratories; telescope of 19 mm aperture, graduated in '/20 an'l w'fn vernier for reading to 1 Minute 13. o. o 53.827. --idem, Figure, with concealed Divided Circle and 2 magnifiers for reading, without prism illustrated in figure 1<>. 0. o This pattern can be highly recommended as tl,<> graduation cannot lir touched by the fingers. 53.828. Model of a Mirror Sextant, of wood, Figure 2. 0. 0 Contact Goniometers and Survey Goniometers: sec p. :>-'!>. Cl. 5081, 1248. l-'l'.i. No. 53835. Mirror Sextants. Reflection. Refraction. 483 53 828. 1 : 5. 53 833. 1 : 7. 53 829. 1 : 4. 53 830. 1 : 4. 53 832. 1 : 2. 53 835. 1 : 6. 53.829. Mirror Sextant, Figure, entirely of brass, with telescope and 4 screening glasses, the vernier giving 5 minutes 53.830. Mirror Sextant, Figure, Large Pattern, entirely of brass, with circle divided on silver, witli telescope, screening glasses, vernier with magnifying glass 53.831. Level Quadrant, for determining angles of altitude to an accuracy of 1 minute . . The level and the object are observed simultaneously in the telescope. The instruments can also be used on vehicles, ships, airships, etc. 53,832. Pocket Heliotrope after Steinheil, Figure, in case . The apparatus gives luminous signals to a distance of 50 km. Refraction, Total Reflection. 33,833. Light-Refraction Apparatus, after Miiller, Figure, for showing the refraction of light- rays in liquids, with etched graduation on ground glass, metal vessel with gap . . . 53.834. - - idem, entirely of glass 53.835. Light-Refraction Apparatus after Miihlenbein, Figure, for demonstrating the laws of reflection and of refraction for solids and liquids; also total reflection; can also he used as a camera obscura (Prakt. Phys., Vol. 2, Part 1) The apparatus lias circular and sine graduation, and has, as accessories, a Plane Mirror, two Half -cylinders of crown and flint glass respectively, also a hollow cylinder for liquids. £. s. d. 4. 10. 0 10.10. 0 3. 15. 0 4. 0. 0 0. 16. 0 0. 12. 0 8. 0.0 Heliographs for Signalling — Particulars on Application. Cl. 1257, 5299, 6041, 1259, 1261, 1296. 31* 484 Refraction. Total Reflection. No. 53836- 53 836. 1 : 5. M 53 839. 1 53 839, 53 840. 1 : 8. 53.836. Light-Refraction Apparatus after Neumann, Figure, also for experiments on simple £ s d. and total reflection, on stand with levelling screws, vertical adjustment, with head graduated for convenience of reading (Ztschr. f. d. phys. u. chem. U. 8. 1894/5, p. 357) 4. 10. 0 53.837. Light-Refraction Trough after Neumann, Figure, simple pattern (Ztschr. f. d. phys. u. chem. U. 7, 1893/4, p. 29), on stand with glass vessel and rubber connecting tubing 0. 16. 0 53.838. Rectangular Glass Box for Experiments on Refraction and Total Reflection (W. D. Fig. 277—283 [263 — 269]) and for the curvilinear propagation of light (W.I)., p. .'5.'! 7 [310]), 25 cm long, 8 cm wide and 16 cm high 0. 18. 0 53.839. - - i d e in, with support and adjustable mirror, F i g u r e s, otherwise as No. 53,838 2. 8. 0 53.840. Rotary Mirror for inserting the glass box of the preceding apparatus, sec Figure, with lever for conveniently adjusting; for use under water 0. 18. 0 53.841. Refraction Box after Stahlberg, F i g u re (Xtschr. f. d. phys. u. chem. V. 15, 1901, p. 65), with 2 watch glasses inserted in one of the side walls One half of the box is filled with floure.-eent water, thr oilier half with tol>;iei-o «nmke. A mirror, which can be rotated and adjusted from the outside, is filled on the lid. In order to observe simultaneously the refraction and reflection occurring for different angles. use is made of a small glass, uith slot diaphragm, which has to lie fixed between the I wo longitudinal s; this glass reflects (by total reflection) the transmitted light in single cones in every dim-lion. CI. I2l)8, 1299, 1286, 1287. 2. 8. 0 No. 53849. Refraction and Reflection. 485 53 849 B. 1:10. 53 849 A. 1:10. 2 watch glasses, one with the convex and the other with the concave side facing outwards, allow the phenomena to be demonstrated experimentally on spherical surfaces. The apparatus can be used either with the light entering from the left or the right. 53.842. - - idem, without Watch Glasses 53.843. Light-Refraction Apparatus after Kepler (M. T. Fig. 133) 53.844. Refraction and Reflection Apparatus, after Weinhold (W. D. Figs. 284, 285), after the style of apparatus No. 53,849, casting the luminous rays in all directions . . . 53.845. - - idem, aftei Grimsehl (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 214), with glass vessel The apparatus can be used with the room half darkened. An arc lamp should be employed as the luminous source. 53.846. Rectangular Glass Vessel, Figure, for showing the curvilinear course of the rays through a medium of unequal optical density, 1 in long 53.847. Apparatus after Hartl for showing the curvilinear path of the rays through a medium of unequal optical density, Figure (Ztschr. f. d. phys. u. chem. U. 9, 1896, p. 116) The apparatus can be filled in a few minutes; the. filling device consists of a funnel, a length of tubing and a tube having a number of small apertures directed downwards and terminating in the bottom of the apparatus. By means of this device the layers can be drawn off and kept for further experiments. 53.848. 10 Bottles, with Glycerine -Water mixtures for above, with 10 — 100% solutions . . 53.849. Apparatus for Reflection and Refraction in Water, after Kolbe, Figs. A and B (Ztschr. f. d. phys. u. chem. U. 19, 1906, p. 1) A glow lamp having a straight filament can be placed inside and above the vessel (surrounded by corresponding slotted cylinders). Given in are 2 Half Cylinders and 3 Whole Cylinders with slots, also 2 white screens. Fig. 53,849 A shows the path of the, rays in demonstrating Kemna's experiment on the refraction and reflection of light when the light passes from water to air. Fig. 53,849 B when passing from air to water. Cl. 6003, 4694, 3831, 3830. £. s. d. 2. 2. 0 0. 16.0 0. 16. 0 1. 2.0 1. 6.0 2. 0.0 0. 6.0 3. 4.0 1321, 486 Refraction. Total Reflection. No. 53 850 — 53 850. 1 : 7. 53 851. 1 : 6. 53852. 1:6. 53 853. 1 : 5 #53,850. Light-Refraction Apparatus, after Tyndall (Tyndall's Drum), Figure, for objective £ i. d. demonstration (M. P. II, 1, Fig. 31 [26]) A cylindrical metal vessel 300 mm diameter can rotate about a polished wood base. In front of a gap a mirror is fitted wth the aid of which a ray of light may be made to penetrate at various angles, according to the rotation of the vessel. The water is coloured with a fluorescent liquid; the ail- space being filled with smoke. # 53,851. --idem, Figure, with a second Mirror and Gap underneath, for 1ot:il reflect ion I * 53,852. Light-Refraction Apparatus after Mach, Figure (M. P. 8lh Edn., II, 1, Figs. 64 and 65; Carls Repertorium 7, 1871) Tiie illustration shows the apparatus from the back, with the device for reflecting the luminous pencil. Tue front of the \csscl is glazed. * 53,853. Apparatus for Determining the Refractive Indices of Liquids, after Bliimd, F i - u i <• (Xtschr. f. (1. phys. u. clicni. I". 2, 1888/9, p. 163) The apparatus con "I a vessel with plale glass walls, and a graduated disk oflJennan silver. about the centre of which 2 levers can rotate. Two rules permit of reading the sine of the incident and refractive angle. The apparatus is arranged for subjective and objective demonstration. * Can be used with the Projection Apparatus. CI. 1285, 3952, 5066, l.".cj. 2. 0.0 2. 10.0 3. 0. 0 2. 8. 0 No. 53 858. Refraction and Reflection. 487 53 855. 1 : 7. 53 857. 1 : 5. * 53,854. Optical Demonstration Apparatus, after Stromann, Figure (Ztschr. f. d. phys. u. £ s- d- chem. U. 18, 1905, p. 71), for demonstrating various fundamental laws relative to ; the theory of light j 8. 0. 0 The following can be proved: Refraction of light; Reflection on Plane and Cylindrical Surfaces; the Bounding Angle and Total Reflection; the passage of the rays through plane parallel plates ; through plano-convex and bi-convex lenses; Polarisation; the warped band of light; Total Reflection in a jet of water; the various properties of refraction possessed by different coloured lights; Chromatic Ab- erration and combination; the Curvilinear path of the rays in a substance of varying density, etc. etc. *.">;?, 855. Apparatus for the Laws of Refraction, Reflection, Total Reflection, etc., Figure 4. 0/0 In the centre a mirror can be introduced for experiments on reflection, or a lens for demonstrating the path of rays in lenses. * 53,856. - - idem, with Perfect Circle * 53,857. Reflection and Refraction Apparatus, Figure The semi-cylindrical glass vessel can be replaced by a plane mirror. The circle is 30 cm diameter and carries two alidades for measuring the angles, and two graduated sliding rules for directly de- termining the sines. 53,858. Reflection and Refraction Apparatus after Silbermann, Figure 8. 0. 0 ci. 4. 12. 0 5. 10. 0 * Can be used with the projection Apparatus. 4174, 3389,5880, 1290. 488 Refraction. Total Reflection. No. 53 859 — 53 859 A. 1:6. 53 860. 1 : 6. 53,859. Optical Disc after Hartl, Figs. A and B (Nos. 1 — 17), for demonstrating the laws of £• s. d. elementary optics (Ztschr. f. d. phys. u. chem. U. 9, 1896, p. 113; M. T. Fig. 134), for experiments with single rays and parallel rays 3. 18. 0 The apparatus is used in an undarkened room with direct sunlight; the entire arrangement is very comprehensive. The following can be demonstrated: the Law of Reflection for PlaneJ Mirrors; the effects and laws relative to the concave and convex mirror; Refraction by a plane parallel plate; prismatic refraction and chromatic aberration; the action of condensing and dispersion lenses; expla- nation of the rainbow. The following pertain to the apparatus: 2 Slotted Sheets with three and seven gaps; Coloured Glass Plates and small Brass Plates; 1 Glass Plane Mirror; 1 Concave and 1 Convex Mirror, of .3,sr>!) B, Nos. 18—20 Eight cones of rays, proceeding divergently from a point, are produced with this apparatus. The following can be demonstrated: the Rule of the Image for the Plane Mirror; the Reflection of the Luminous Rays issuing from a point, on Concave and Convex Mirrors; existence of the real Image; Refraction by a Condensing Lens or Aberrating Lens of the Rays issuing from one point; Action of Spectacles; Action of Diaphragms. TJe additional apparatus consists of a separate ground crystal phite on iron stand, one bi-conrex crystal glass lens and one diaphragm. 53,861. Reflector for reflecting the Solar Rays 1. 6. 0 (I. \-2. 0 Liquid Prisms for determining Kei'rurtive Indices: see page 501 and ">02. CI. 6100, 3677. Kr>. 533S1. Refraction and Reflection. 489 17 53859 B, 53860. 1: 11. Demonstrations with the Hartl Optical Disc. Cl. 6511. 490 Refraction. Total Reflection. No. 33362 — 53 862, 53 859, 53 863. 1 : 6. 53863. 1:4. 53,862. Polarisation Apparatus for placing on the Hartl Optical Disc, Figure (Ztschr. f. £• d. phys. 11. chem. U. 19, 1906, p. 105), without glass preparations ......... 2. 8. 0 The following can be shown: uniform reflection of ordinary unpolarised Light; Polarisation by Reflection; Polarisation by repeated Refraction; chromatic Polarisation; Phenomena in convergii Polarised Light. The apparatus consists of 1 rectangular Sheet Iron Plate fixed on the optical disc; 1 plate Slab and 1 set glass Plates as interchangeable Polarisers; 1 rotary black plate glass Slab as Analyser; 1 Stage arranged between the former; 1 small Projection Screen; 1 Condensing Lens for producing converging Light and 1 Sheet Iron Scre«n for completely shadowing the Projection Screen. Fig. 53,862 shows the image when using an unaxial crystal of sodium nitrate. 53,863. Rapidly annealed Glasses, Figure, for the Hartl Polarisation Apparatus, in wood mount, for producing interference images. Each (from selection) o. .!. The glasses show in polarised light the inteiference images obtained in Fig. 53,863. Two crossed glasses can also be used (see No. 26a and 27 a in Fig. 53,863): it is advisable in this case to employ the baseplates listed under No. 53,864, which are supplied with a separate mount so as to allow the upper plates to be easily interchanged. 53,864. Baseplate for Crossed Glasses for producing Interference linages, comprising a rapidlv annealed glass with special wood mount; for use in conjunction with the rapidly annealed glasses listed in the preceding item Kadi (I. 4. <> The type of glasses (1) (2) and (7) as per Fig. 53,863 is specially .-unable inr baseplates. l'nle»> otherwise stated, triangular baseplate No. -2 is supplied. The mount of the baseplate is provided with special clamps, one of which can easily be loosened so that the upper plate eau lie quickly interchanged. 53,864 a. Projection Lens for projecting the interference figures on the screen, the si/e of the image being 50 cm diameter. This lens is fitted on the Polarisation Apparatus in place of the small screen o. 4. t> C1.3877<1, 3678 '. No. 53 870. Refraction and Reflection. 491 53 866. 1 : 12. 53 869. 1 : 6. £. ,8. (1. 18. 0. 0 3. 0.0 53.865. Universal Optical Apparatus after Bosenberg, Pigs. A and B (Ztschr. f. Instrumenten- kunde 7, 1887, p. 323) It is possible to show with the apparatus all the laws of reflection and retraction on minors, lenses and prisms as well as the splitting up of white light into the spectrum colours and the recorn- position of the same. In addition, the microscope and the telescope can be explained with the apparatus. The upper part of the apparatus can be fixed on the frame in three different positions. Accessories: 2 Paraffin Lamps of special type; 1 plane Mirror; 1 concave Mirror ; 1 convex Mirror; 4 bi-convex Lenses of different focal length and diameter; 1 bi-concave Lens; 1 plano-convex Lens; 1 glass Cube; 1 Apparatus for proving reflection and refraction, Fig. B; 2 Prisms, one of these being of flint glass. (For larger pattern apparatus see No. 53,867.) 53.866. Auxiliary Apparatus for explaining the Measurement of the Velocity of Light by the Fizeau and Foucault methods, Figure 53.867. Universal Optical Apparatus after Bosenberg, larger pattern, 2 m higher 30. 0. 0 53.868. Apparatus for Demonstration of the Refraction of Light in Glass and in a Glass Prism, Figure 2. 10. 0 On a stand is iixcd a divided circle, which is capable of rotation, and in the centre of wnich can be fitted a semi-circular ground glass body or a prism of 30 mm side. 53.869. Hollow Prism after Silbermann, Figure, for showing that the deflection increases when the refractive angle increases (M. P., 8th Edn., II, 1, Figs. 84 — 86) '. The prism can be filled with any aqueous, alcoholic or corrosive liquid, as it is cemented in the fire. The box is rotary and has a graduation. 53.870. Glass Plate for Refraction Experiments (M. T. p. 179), 2 cm thick, si/e 10x15 cm 0. 4.0 Cl. 1313, 1315, 1293, 4671, 1294. 3. 12: 0 492 Refraction. Total Reflection. No. 53871 — 1 Reflection! on plane 3. Refraction when passing 6. Refraction in Prism. 10. Bi-conyex Lens Mirror. from Glass to Air. 7. Refraction in Liquids. 11. Reflection < 2. Refraction when passing 4. Total Reflection in Glaat. 8. Plano-concave Lent. from Air to Gla.-s. 5. Refraction inl'laneGlasses 9. Bi-eoncave Lens. Mirror. 12. Reflection on Convex Mirror. 53 871 B. 1 : 5. Some Demonstrations with the Kolbe Refraction Apparatus. CI. 1300,5795,5017, 6512. No. 53 878 b. Light Refraction Apparatus. 493 53 876. 1 : 5. 53878. 1:8. 53 878 a. 1:9. 53.871. Light-Refraction Apparatus after B. Kolbe (Ztsehr. f. d. phys. u. chem. U. 9, 1896, £• £• d. p. 20, and 13, 1900, p. 9), Figs. A and B, diameter of glass disc 360 mm ..... 9. 10. 0 When using parallel light experiments can be made with the apparatus on reflection on plane mirrors, refraction of the light when the rays pass from the thin into the denser medium and vice-versa (air-glass, glass-air, water-air, etc.), total reflection, refraction in plane parallel glasses, minimum of de- flection, refraction in prisms and lenses, reflection on cylindrical mirrors. The apparatus consists essentially of a ground glass disc capable of rotation in rollers, provided with a suitable sine graduation and carrying a spring clip in order to easily interchange the light- refracting bodies. The following are given in with the apparatus: 1 Screen with two diaphragms; 1 cardboard Disc with marked degree graduation; 4 Diaphragms with 1, 3, 7 and 9 gaps; 1 Reflecting Mirror; 1 solid half -cylinder of Glass; 1 hollow half-cylinder of Glass; 1 flint Glass Prism; 1 Glass Block; 1 cylindrical Cendensing Lens and 1 cylindrical dispersion Lens each 60 mm focus ; 1 concave and 1 con- vex Mirror each 100 mm radius of curvature; 1 Glass Body with two plane parallel surfaces and a refracting angle of 45° and one of 60°. 53.872. - - idem, with glass disc 240 mm diameter 8. 0. 0 53.873. Light-Refraction Apparatus after Reusch, movable (W. D. Fig. 289 [272]) .... 1. 4.0 * 53,874. --idem, for the Projection Lantern, Figure 0. 16. 0 53,875. Light-Refraction Apparatus after Pfaundler (M. P., 9lh Edn., II, 1, Figs. 46 and 47), for demonstrating the minimum deflection in the prism 2. 0. 0 * 53,876. Apparatus for Refraction in Plane Glasses, Figure, for showing the apparent displacement of the object by moving a plane parallel plate in front of an object . 0. 6. 0 53.877. Niemoller's Apparatus for the Mechanical Demonstration of the Law of Refraction, Figure (Fr. phys. Techn. I, 2, Fig. 2212; Ztsehr. f. d. phys. u. chem. U. 5, 1892, p. 139) • 1.16.0 Wood Protractor on Stand, Fig. 51,491, p. 229, after Friedr. C. G. Miiller (M. T., Figs. 6, 14, 15), for measuring angles in mechanics and optics 2. 10. 0 53.878. Collection of Apparatus for Demonstrating the Laws of Reflection and Refraction, Figure, in box | 7. 0. 0 1 Plane Mirror 100 mm diameter; 1 Concave Cylindrical Mirror 90 mm diameter; 1 Convex Cylindrical Mirror 90 mm diameter; 1 Convex Lens 100 mm diameter; 1 Flint Glass Prism 45 mm side; 1 Water Trough, 1 Ground Glass Screen. 53,878 a. Refraction Apparatus after Stahlberg (Ztsehr. f. d. phys. u. chem. U. 15, 1902, p. 69), Figure, on stand with one tube each for water and benzol 3. 0. 0 This apparatus is constructed after the style of the Reusch light-refraction apparatus. It can be adjusted for the refraction-ratio 4 : 3 (air to water) and 3 : 2 air to glass and air to benzol) and can be used with the light penetrating either from the right or left. 53,878 b. Light-Refraction Apparatus after Stahlberg, exactly as No. 53,878 a, but without benzol tube . 2. 15. 0 * Can be used with the Projection Apparatus. Cl. 5794, 1355, 1291. 494 Refraction. Total Reflection. No. 53 879 — 53 880. 1 : 3. O 53 886. 1 : 3. 53881. 1:6. 53 883. 1 : 7. 53 884. 1 : 4. 53 888. 1 : 5. 53,879. Small Tube with Mercury, for demonstrating Total Eeflection (W. D., Fig. 290 [273]) £. s. (1. 0. 4.0 53,880. Small Tube with Cedarwood Oil, P i g u r e, for showing the disappearance of reflection at the edge of equally refractive media (W. D., Fig. 292 [275]) 0. 4. 0 * 53,881. 2 Glass Plates with air gap, F i g u r e, for proving Total Eeflection (W. D., p. 378 [346]) 0. I. o * 52,590. Calladon's Apparatus for Total Reflection in a Jet of Water (Light Fountain): see Fig. 52590, p. 352) 2. 0. 0 * 52,589. - - smaller and without base, see Fig. 52,589, p. 352 0. 16. 0 53,882. Prism in which a vertical edge is cut away in the form of a vase. The figure appears, by total reflection, as a hexagonal bodv with glistening silvery surfaces (M. P., 8lh Edn., II, 1, Fig. 80) 0. 5. 0 * 53,883. Apparatus for Total and Partial Reflection in Glass Rods, after Hartl (Ztschr. f. d. phys. u. chem. U. 19, 1906, p. 134), Figure, with 1 bent rod of transparent glass which reflects the entire light on a small screen, and two frosted glass rods which reflect only a portion of the light; with stand 1. 5. 0 53.884. 2 Rectangular Prisms of Plate Glass, Figure, 30 mm base and 30 mm height, j on Stand, for showing the difference between ordinary reflection in glass and total reflec- tion (M. P., 8th Edn., II, 1, Figs. 77 and 78) . . * 1. 10. 0 53.885. - - i d e m, 45 mm base-length and 45 mm height 2. 0. 0 53.886. Glass Cube, after Rosenberg, for total reflection, Figure 0. 4. 0 The light does not pass through two adjacent walls of the transparent cube. 53.887. Glass Body after Kolbe, with two plane parallel surfaces, a refracting angle of 45° and one of 60° 0. 8. 0 53.888. Glass Box for Total Reflection, after Hartl, Figure 0. 8. 0 The box is half filled with water; the corrugated glass bottom appears of silvery brightness on the upper surface when viewed from above, and as if the vessel were filled with ink, on the under side. When viewed laterally the contents can be recognised as water. Looked at from the back, the upper part seems darker than the lower, by virtue of total reflection, when the box is held up to a strong light. 53.889. Built-up Model of a Convex Lens and of a Concave Lens (Polyprism), after (irimsehl, for demonstrating the path of the lays (/tschr. f. d. pliys. u. chem. V. 20, 1!H)7, p. 215). consisting of two parallelepepedic glass vessels for filling with water, two similar vessels of trapezoidal section, which can be built up together into lenticular bodies; 1 table stand for same and 1 stand with 4 mirrors for conducting the luminous rays ... 2. 14. 0 53.890. Model of a Convex Lens, after Miililenbein. Figure, \\ith fixed and movable coloured rods for demonstrating the path of the rays and the relations between object and image 1. 4. 0 53.891. Model of a Concave Lens, after Miililenbein, same pattern as above I. I. C'l. 1316. 13-Jci, * Can be used with the Projection Apparatus. i;m, 3927, 1319, .v.:i. No. 53 906. Refraction and Reflection. 495 53892. 1: 10. 53 898. 1 : 10. 53 895. 1 = 2. 53.892. Demonstration Apparatus for the Refraction of Light by convex and concave lenses, £• s. d. Figure, after Neumann (Ztschr. f. d. phys. "u. chem. U. 8, 1895, p. 268) 1. 16. 0 The apparatus comprises two angles formed of brass strips (incident and refracted ray). The 149° angle is for the convex and that of 154° for the concave lens. The variable size and width of image can be demonstrated with the aid of the apparatus. 53.893. 2 Slabs with Pair of Pulleys and velvet Supports, for showing mechanically the deflection of the luminous rays in prisms, plates and lenses (M. P., 8th Edn., II, 1, Fig. 370) . 1. 12. 0 53.894. 6 Lenses in simple Case, Figure, plano-convex, bi-convex, concave-convex, plano- concave, bi-concave, convex-concave, 50 mm diameter, Figure 0. 10. 0 53.895. 6 Lenses in case, Figure, plano-convex, bi-convex, concave-convex, plano-con- cave, bi-concave, convex-concave, 65 mm diameter 0. 16. 0 53.896. 6 Lenses in Case, smaller: plano-convex, bi-convex, concave-convex, plano-concave, bi-concave, convex-concave, 40 mm diameter, in mount with metal hafts 1. 10. 0 53.897. - - idem, and, in addition, 2 Cylindrical Lenses and 1 Achromatic Lens, also 2 Stands 2. 16. 0 ."..'i.sux. Piano-Convex-Lens 200 mm diameter, Figure, on tripod, for demonstrating spherical aberration and chromatic aberration of the refracting light-rays with the aid of two diaphragms, one with a number of holes on the edge and one with round hole in centre 2. 10. 0 .">.'!, *99. Achromatic Lens System, on Stand, one lens fixed and the other movable in hinge; diain. 30 mm, focal length 30 cm 1. 5. 0 r>:;.'.Mto. --idem, 40 mm diameter, focal length 30 cm 1.10.0 Achromatic Lenses, in mount with haft, without stand. List No. 53,901 53,902 53,903 53,904 53,905 Diameter mm 50 60 70 80 100 Focal Length mm 300 500 500 500 800 £ 1.0.0 1.10.0 2.0.0 2.10.0 3.12.0 53.906. Stand for above . . 0. 5. 0 , Cl. 1348, 1349, 1353, 1352. 496 Refraction. Total Reflection. No. 53 907 — 53 920. 1 : 5. 53 924. 1 : 8. £. s. (1. 53.907. Cylindrical Lens 60 mm diameter, in mount, on stand 1. 4. 0 53.908. — idem, 80 mm diameter 1. 10. 0 53.909. 2 Convex Lenses 80 mm diameter and 500 mm focal length, on tall stands; can be ; used for a number of experiments, together 1. 10. 0 Hollow Lenses, bi-convex, with lateral opening for introducing liquids: List No. 53,910 53,911 53,912 53,913 53,914 Diameter mm 50 80 105 130 155 f 0.5.0 0.7.0 0.8.0 0.10.0 0.13.0 - idem, plano-convex: List No. 53,915 53,916 53,917 53,918 53,919 Diameter mm 50 80 100 130 160 £ 0.5.0 0.7.0 0.8.0 0.10.0 0.13.0 53.920. Lens Stand, Figure, in which can be mounted any lens from 25 to 50 mm diameter 53.921. --idem, for lenses from 50 to 100 mm diameter 53.922. — idem, for lenses from 100 to 150 mm diameter 53.923. Hollow Concave Lens (plano-concave) for use as a condensing lens under water (W. D., p. 384) 53.924. Lens Apparatus after Dr. Zwick, Figure. (Dr. Zwick, 150 optische Versuche usw., pp. 49 et seq. ; see No. 53,928), with lenses 50 mm diameter, for showing the action of condensing and dispersing lenses and the camera obscura, the human eye and spectacles The apparatus consists of one optical bench of 60 cm useful length, 1 Lens Holder; 2 curved Glass Disks, for representing the cornea and the iris, with the pupil, of the eye; 3 convex Lenses of 6, 8 and 11 cm focal length, in mount; 1 bi-convex Lens of 30 cm focal length with mount and haft; 1 bi-concave Lens of 15 cm focal length, with mount and haft; 1 Stage; 3 Stands; 1 Ground Glass Disk with mount; 1 Wire Cone; 1 Disk perforated in centre, with rotary disk and various diaphragm - apertures; 1 Ring for stretching paper; 1 small Tripod. 53.925. - - idem, larger Pattern; diameter of Lenses 80 mm 53.926. Optical Apparatus ufter Dr. Zwick, for the Fundamental Theories of Optics, with optical bench 2 m long and the accessories listed below, which also contain the accessories of the lens-apparatus after Dr. Zwick, No. 53924 (Dr. Zwick, 150 optische Versuche /m Veranschaulichung der Grundlehren der Ausbreitung, Spirgeliing und Bret-hung des Lichts; sec No. 53,928) The constituents of the apparatus are: 1 optical Bench; 1 Lens Holder (as No. 53,924); 2 curved Glass l>isks representing the cornea and the iris, with the pupil, of the human eye; 3 bi-conve\ I.rn-"- of 9, 11, 15 cm focal length, with mounts; 1 bi-convex Lens of 30 mm focal length, with mount and haft; 1 Bi-concave Lens of 15 cm focal length with mount and haft; 1 Stage; :> Stands; 1 Ground Glass Disk with mount; 1 Wire Cone; 1 centrally pierced disk with pivoting disk and different diaphragms 1. 0. 0 1. 4.0 1. 10. 0 0. 10. 0 4. 0.0 (i. 0. 0 11.0.0 Cl. 1354. 4002. No. 53 930. Lenses and Lens Apparatus. 497 53926. 1:14. 53929. 1:16. 1 ring for stretching paper, 1 small tripod, 1 carrier for 1 candle, 1 carrier for 4 candles, 1 pivot holder, 3 silvered plane mirrors (glass) 10, 5 and 3 cm diam., 1 Concave Mirror (German Silver) 15 cm diam. and 5 cm focal length, 1 flint glass Prism, 1 Screen with adjustable gap, 1 Glass Cube 5 cm side, 1 Glass Lens for supplementing the terrestrial telescope, 4 Glass Plates (window glass, ground, red and green glass 8 cm square), 1 rectangular Trough 8 cm square, 1 Paper Screen, 1 Light Screen, 1 Spirit Lamp, 1 Protractor, 1 small Glass Flask 4 cm diam., also Diaphragms, Pasteboard and Tissue Paper. 53.927. --the same apparatus, fitted with the accessories of the larger Lens Appa- ratus No. 53,925, instead of No. 53,924, fittings otherwise the same as before . . . 53.928. Pamphlet by Dr. Zwick: "150 optische Versuche zur Veranschaulichung der Grund- lehren der Ausbreitung, Spiegelung und Brechung des Lichtes", bound 53.929. Optical Bench, Figure, with accessories for demonstrating the path of rays in lenses and concave mirrors, for demonstrating the microscope and telescope, the Bunsen Photometer, etc The optical bench consists of a 2 m long measuring bar, divided in centimetres, and constructed of maple-wood; it rests on two massive brass pillars, is mounted on a mahogany board and provided with 14 stands for raising and lowering the lenses, diaphragms, etc. The following are included with the apparatus: 3 bi-convex Lenses, 1 bi-concave Lens, these being selected so that they can be used for setting up the microscope and the terrestrial, astronomical and Galilean telescope; also 1 concave Mirror (glass) 120 mm diam., silvered on front and closed by a cap; 1 flint glass Prism, 1 paraffin Lamp, 1 Gap with micrometer screw, 1 white Screen for receiving the images, 1 Screen for concave mirror images, 1 Diaphragm, 1 Light Holder with one light, 1 Light Holder with 4 small lamps for photometry, and 1 White Screen with grease spot. 53.930. - - idem, fittings of simpler pattern, with the accessories previously mentioned, but without Prism; mirror only 90 mm diam.; gap without micrometer; and with only 6 stands Optical Benches Nos. 53,929 and 53,930 can also be used as Melloni Apparatuses: all parts fitting the same can be obtained from us. Further Optical Benches for explaining the Telescope, Microscope, etc., etc.: see later on in list. 13. 0.0 0. 3.0 12.10.0 £ s. d. 9. 0.0 Cl. 4001. 1358. 32 498 Refraction, Total Reflection. Optical Measuring Instruments. Spectrum Analysis and Synthesis. NO. 53931- 53 932. 1 : 6. 53 933. 1 : 6. £ s. (1. lo. 10.0 53.931. Optical Apparatus after Mach, Figure, as improved by Kolbe, for explaining the phenomena of reflection and refraction with visible beams of light (Ztschr. f. d. phys. u. chem. U. 7, 1887, p. 77) The apparatus consists of a box 1 in long, with iron legs, the walls being formed by glas> plates. and in which an optical bench is set up. The sliders of the bench can be adjusted from outside. A graduation is provided on the front wall and permits of reading the distances between lenses. By inserting various gratings and frames with differently arranged coloured glasses at the narrow end, the experiments are carried out in the box, which is filled with smoke (reflection of spherical mirrors, refraction of light in lenses and prisms, demonstration of chromatic and spherical aberration). The following pertain to above: 3 lenses in mounts, 120 mm diam.: 2 ground mirrors, convex and concave, 120 mm diam.; 1 prism, 1 screen, 3 gratings of different fineness, 1 small plane mirror on adjustable stand, 2 sliders with coloured glass, 2 cover plates. 53.932. Supplementary Apparatus for Refraction and Total Reflection in Liquids, Figure, and Stand with 2 adjustable plane mirrors, for Apparatus No. 53,931 3. 0. 0 The apparatus is provided on front side with circular graduation, degree and sine graduation. 53,932a. Fillet with 2 lens mounts and small glow lamp, also lens mount on base, after (irim- sclil, for measuring the radius of curvature of a convex lens; for Students' use (K. (irim- selil, Ausgewahlte pliysikal. Sehiileriibungen, Fig. 13) 53,932b. 30 Lenses, arranged in dioptres, in box, for use with preceding apparatus and with apparatus for determining focal length. No. 53,932c, and the Grinisehl Diffraction Apparatus No. 54,549, etc 1. 10. 0 0. lo.o Cl. 1369, 1360, 1367. No. 53974. Optical Measuring Instruments. 499 53 934. 1 : 7. 53935. 1:3. 53,932 c. 2 Glow Lamp Holders and 1 Lens Mount on wood pillar, with glow lamps and mea- suring rod, after Grimsehl, for determining the focal length of convex lenses and of concave lenses in practical school work (E. Grimsehl, Ausgewahlte physikal. Schiiler- iibungen, Figs. 23—26) Lenses for above: see No. 53,932 b. Optical Measuring Instruments. 53.933. Jamin's Circle, Figure, for all kinds of measurements on reflection, refraction and polarisation (Jamin, cours de physique) 53.934. Total Reflectometer after Kohlrausch, Figure (W. u. E. phys. prakt. Fig. 159), for determining the refractive indices of liquids and solids Spectrum Analysis and Synthesis. 53,!»35. Glass Prism, F i g u r c, polished, 100 mm high and equal-sided, length of side 25 mm Plate Glass Prisms, equilateral, with three polished surfaces; height — length of side: List No. 53,936 53,937 53,938 53,939 53,940 53,941 Length of Side mm 30 35 40 45 50 60 £ 0.5.0 0.6.0 0.8.0 0.10.0 0.12.0 0.15.0 Plate Glass Prisms, long pattern, equilateral, with three polished surfaces: List No. 53,942 53,943 53,944 53,945 53,946 53,947 53,948 Length of Side mm 25 30 35 40 45 50 60 Height mm 50 60 70 80 90 100 120 £ 0. 8. 0 0. 10. 0 0. 12. 0 0. 16. 0 1. 0. 0 1. 4. 0 1. 10. 0 Crown Glass Prisms, equilateral, with three polished surfaces; height == length of side: List No. 53,949 53,950 53,951 53,952 53,953 53,954 Approx. Length of Side mm 30 35 40 45 50 60 £ 0. 10. 0 0. 12. 0 0. 15. 0 0. 18. 0 1. 0. 0 1. 5. 0 Crown Glass Prisms, long pattern, equilateral, with three polished surfaces: List No. 53,955 53,956 53,957 53,958 53,959 53,960 53,961 Approx. Length of Side mm 25 30 35 40 45 50 60 Approx. Height mm 50 60 70 80 90 100 120 £ 0. 15. 0 1. 0. 0 1. 5. 0 1. 10. 0 1. 15. 0 2. 0. 0 2. 10. 0 Prisms made of glasses whose refractive index is greater than 1.7, icrease 100% in price. Flint Glass Prisms, equilateral, with three polished surfaces; height == length of side: List No. 53,962 53,963 53,964 53,965 53,966 53,967 Approx. Length of Side mm 30 35 40 45 50 60 £ 0. 10. 0 0. 12. 0 0. 15. 0 0. 18. 0 1. 0. 0 1. 5. 0 Flint Glass Prisms, long pattern, equilateral, with three polished surfaces: List No. 53,968 53,969 53,970 53,971 53,972 53,973 53,974 Approx. Length of Side mm 25 30 35 40 45 50 60 Approx. Height mm 50 60 70 80 90 100 120 £ 0. 15. 0 1. 0. 0 1. 5. 0 1. 10. 0 1. 15. 0 2. 0. 0 2. 10. 0 52.10.0 9. 0.0 0. 2.0 £ s. d. 0. 12. 0 (Jl. 6030, 1323. 32* 500 Spectrum Analysis and Synthesis. No. 53975 - 53 988/94. 1 : 4. 53 995. 1 : 3. 53 996. 1 : 6. £ s. d. Prisms of Rock Crystal, the refracting edge ground perpendicular to the optical axis, with two polished square surfaces: List No. 53,975 53,976 53,977 53,978 53,979 53,980 Side, approx. mm 20 25 30 35 40 50 £ 1.5.0 1.10.0 2.0.0 2.10.0 3.5.0 4.10.0 The rays which traverse the prism at minimum deflection are parallel to the optical axis. Prisms of Rock Crystal, the refracting edge ground parallel to the optical axis, with three polished square surfaces, showing double refraction: List No. 53,981 53,982 53,983 53,984 53,985 53,986 Side, approx. mm 20 25 30 35 40 50 £ 1.5.0 1.10.0 2.0.0 2.10.0 3.5.0 4.10.0 Prism Stands, with height adjustment, cf. Figs. 53,987 — 94; the prisms can be rotated about two horizontal axes perpendicular to each other. List No. 53,988 53,989 53,990 53,991 53,992 53,993 53,994 » Without Prism £ 0. 18. 0 0. 18. 0 1. 0. 0 1. 0. 0 1. 4. 0 1. 4. 0 1. 10. 0 The preceding prices include the cementing in of the prisms if the latter are ordered at the same time as the Stands. 53.995. Crossed Prisms after Newton, Fig. 53,995, of plate glass, side 30 mm (Gan.-Man. Fig. 364; Gan.-Atk. Fig. 554) ............ .............. 2.16.0 53.996. Double Prism on Stand, Figure, of Crown and Flint Glass cemented together, 25 mm side, 50 mm length; for showing the varying refraction of different media . 1.16.0 53.997. --idem, 30 mm side, 60 mm long ..................... 2. 0. 0 53.998. Polyprism on Stand, of three kinds of glass cemented together, 25 nun side, 40 mm long ..................................... 2. 0.0 53,999. - - i d e in, 30 mm side, 60 mm long ..................... 2. 10. 0 54.000. --id o in, F i g n r c, of five kinds of glass cemented together, 25 mm side, 40 nun long, on Stand ................................ 2. lo. u 54.001. -- idem, .30 mm side, 60 mm long ..................... 3. 5. 0 54.002. Polyprism, of four kinds of glass :ui mm side, 40 mm long, on Stand ............................. 3. 0. d 54.003. --idem, 30 mm side, 60 mm long ..................... 4. 0. 0 Stages for Prisms: see. Nos. 54,061, p. 503. ci. 1324, isss, 5769. Nci. 54015. Solid Prisms. Hollow Prisms. 501 54 007. 1 : 2. 54 006. 1 : 2. 54000. 1:4. 54012. 2:5. 54009. 54 010. 1 : 5. 54015. 3 £ s. d. 54.004. Carbon Bisulphide Prism, flask form, Figure . 0. 16. 0 54.005. --idem, of black glass, with plate glass sides . 0. 18. 0 54.006. Hollow Prism of solid glass with a perforated aperture and two plate glass discs, Figure (Gan.-Atk. Fig. 535) 0. 14. 0 54.007. Hollow Prism after Meyerstein, pierced, Figure, with detachable surfaces and accurately ground angle of 35°, in metal mount, aperture 20 mm (M. P. II, 1, Fig. 159 [177]; W. u. E. phys. Prakt., Fig. 147), for determining the refractive indices of liquids 3. 0.0 •VI, 008. -- idem, with quartz walls 4.10.0 54.009. Hollow Prism of solid glass, after Steinheil, Figure, with pierced aperture 20 mm diameter, closed by two plane parallel glasses which are pressed on to the glass body 4. 10. 0 54.010. Hollow Prism on Stand, with two compartments, Figure, in brass mount . . 2. 4. 0 54.011. - - idem, with three compartments 2. 16. 0 54.012. Hollow Prism of Crystal Glass, Figure, assembled with acid-proof cement fused in the fire, for any liquids — alcohol, water, acids, etc.; one side blackened, with care- fully ground in glass stopper; outside dimensions: height 75 mm, side 35 mm ... -0.10.0 54.013. -- idem, height 90 mm, side 60 mm 0.16.0 54.014. - - idem, height 100 mm, side 80 mm 1. 0. 0 54.015. Hollow Prism with Partition Wall, of crystal glass, Figure, for filling simulta- neously with two different liquids, with wood support. Outside dimensions: Height 100 mm, side 60 mm . . 1. 0. 0 Cl. 1328, 1321), 1330, 1333. 1335, 1334, 1331, 1336. 502 Spectrum Analysis and Synthesis. No. 54016 — ; 54019, 1:4. 54022/27. 1:2-1:4. 54 020. 1 : 2. 54 029/54 031. 1 : 6. 54 033. 1 : 6. 54034. 1:8. 54,016. Hollow Prism, trough form, with loose cover, with one compartment, 50 mm lorn:, 55 mm side . 54.017. --idem, with two compartments 54.018. - - idem, with three compartments 54.019. - - idem, with four compartments, Figure 54,020. Differential Prism (Double Trough) after Hallwachs, Figure, for determining small differences in refractive ratios of liquids (Wied. Ann. 50, p. 577; Kohlrausch, Lehrb. d. prakt. Phys., 10th. Edn., p. 260); all three sides traversed by the light are of plate glass 54,021. --idem, all three surfaces of plane parallel glass Wernicke Liquid Prisms, Figure: List No. 54,022 54,023 54,024 54,025 54,026 54,027 Free Aperture, abt. mm 20x20 27x27 34x34 41x41 45x45 50x50 £ 2. 15. 0 3. 0. 0 4. 0. 0 5. 0. 0 8. 0. 0 13. 0. 0 The prism is filled with cinnamic ethyl ether; it is mounted in wood to prevent temperature variations: it is supplied with direct or deflected ray. 54,028. - - idem, constructed round; can be taken apart for cleaning, aperture 30 mm . In this type all cement is eliminated. Direct-Vision Prisms after Konigsberger, F i g u r e, filled with durable liquid (Ztschr. f. d. phys. u. chem. U. 22, 1909, p. Ill; Phys. Ztschr. 9, p. 727): List No. 54,029 54,030 54,031 Free Aperture mm 25 X 25 40 x 40 55 X 55 £ 1.10.0 2.10.0 4.10.0 54.032. Gas Prism after Biot and Arago, for determining the absolute coefficient of refraction of air and other gases,, with barometer gauge, brass mount and stopcock, for setting up on the air-pump (Gan.-Atk. Fig. 536) 54.033. Variable Angle Prism, Figure, for taking various liquids, simple pattern . . . 54.034. - - i d e in, Figure, better construction, with degree graduation 54.035. Prism Apparatus, Figure, with three prisms for demonstrating the achromatic Prism and the Direct-Vision Prism (W. D. Fig. 298 [281]) Cl. 1338,^98. Diffraction Gratings: see Section "Diffraction of Light". £ s. d 0. 9.0 0. 16. 0 1. O.o 1. 6. (I 1.13.0 5. 0.0 5. 0.0 3. 0.0 13. 2.0 2. 10. 0 1'. 8.0 1341. Xo. 54069. Hollow Prisms, Prim-Combinations. Rainbow. 503 54 068. 1 : 5. 54 035. 1 : 6. Achromatic Prisms, 54 036/39. 1 : 5. 54 062. 1 : 4. 54 063. 1 : 6. Figure, on stand, arranged for separating the prisms : List No. 54,036 54,037 54,038 54,039 Side-Length, abt. mm 30 35 40 50 £ 1.8.0 1.12.0 2.0.0 2.8.0 Prism System after Amici, with direct vision, triple, consisting of 1 flint glass prisma and two crown glass prisms: 54,040 54,041 54,042 54,043 54,044 54,045 10 15 20 25 30 35 1.0.0 1.10.0 2.0.0 2.10.0 3.5.0 4.5.0 List No. Side, abt. mm (a) Without Mount . £ (b) With Mount, Dia- phragm and Stand £ 2.0.0 2.10.0 3.0.0 3.10.0 4.10.0 5.10.0 - idem, quintuple, consisting of two flint glass and three crown glass prisms : 54,052 38 8.0.0 54,059 60 12. 10. 0 List No. 54,046 54,047 54,048 54,049 54,050 54,051 Side, abt, mm 10 15 20 25 30 35 (a) Without Mount .£1.5.0 2.5.0 3.5.0 4.10.0 5.15.0 7.0.0 (b) With Mount, Dia- phragm and Stand £ 2. 5. 0 3. 5. 0 4. 5. 0 5. 10. 0 7. 0. 0 8. 5. 0 9. 10. 0 Rutherford's Prisms: List No. 54,053 54,054 54,055 54,056 54,057 54,058 Aperture, mm 25 30 35 40 45 50 £ 2. 10. 0 3. 0. 0 3. 15. 0 5. 0. 0 6. 5. 0 9. 0. 0 54.060. Model of the Porro Prism-combination after Weinhold (W. D. Fig. 319) 54.061. Adjustable Rotary Stage for setting up any kind of Prism 54.062. Pyramidal Rectangular Prism, Figure, of crystal glass, in mount on stand, for producing four spectra 54.063. Crystal Glass Cone, F i g u r p., in Mount on Stand, for producing a round spectrum (rainbow) 54.064. - - i (I e m, of flint glass, in mount, on Stand 54.065. - - i d e m, of crown glass, in mount, on Stand 54.066. Crystal Glass Cone, without mount or stand 54.067. Cone, after Thompson, for producing a Rainbow, on Stand, cf. Fig. 54,068 . . . The vessel above the cone is filled with cinnamic ethyl ether. 54.068. - - idem, without stand, Figure... L 4,069. Rainbow Apparatus after Grimsehl (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 213), consisting of a glass vessel representing the rain-drop, on Stand, and a receiving screen with gap Large Optical Benches with Accessories for Objectively Projecting the Spectrum, etc.: see further on in list. 1. 4.0 0.16.0 2. 0.0 1. 5.0 2. 5.0 2. 0.0 0. 10. 0 5.15.0 4. 5.0 2. 0.0 CI. 4924, 8107.1343,1346,1347. £ B. d. 504 Spectrum Analysis and Synthesis. No. 54070 - 11 54070. 1:8. 54 072. 1 : 16. 54078. 1:9. * 54,070. Apparatus for Demonstrating the Spectrum and the Fraunhofer Lines, Figure, £ s. d. consisting of a flint glass prism of 40 mm side and an achromatic lens 50 mm diam., fitted together on one stand, the prism rotary 3. 0. 0 The apparatus can be placed both in front of the heliostat or the projection lantern, as it has a tall adjustable stand. * 54,071. - - idem, with prism of 45 mm side and achromatic lens 60 mm diameter ... 4. 0. 0 * 54,072. Apparatus with 7 Mirrors, Figure, for re-combining the light split up into the spectrum colours; consisting of 7 plane mirrors 55 mm diam., in mounts, movable in all directions, on adjustable stand 4. 0. 0 * 54,073. - - idem, smaller, with mirrors 40 mm diameter 3. 0. 0 * 54,074. - - idem, with three mirrors 40 mm diameter 1. 10. 0 * 54,075. Laminated Mirror after Costing (Ztschr. f. d. phys. u. chem. U. 11, 1898, p. 132; M. T. p. 186) 2. 10.0 * 52,043. Oscillating Prism, Fig. 51,949 B, p. 278, for mixing the spectrum colours, for the Whir- ling Table (M. P., 8th. Edn., II, 1, Fig. 137), prism 60x30 mm; price without Whirlin- Table '. 1.5.0 #52,044. -- idem, prism 70x35 mm, see No. 52,044, p. 285 1.10.0 52.034. One Set Colour Discs, 7 different mono-chromatic discs and one with the seven colours of the spectrum (Gan.-Atk. Figs. 562/64), see No. 52,034, p. 284 0. 5.0 The mono-chromatic discs are slotted in accordance with Maxwell's method, in order to produce mixed colours and white. 52.035. Newton's Colour Disc with the 7 Spectrum Colours, painted as clearly as possible on a metal disc, giving white when rotated, 120 mm size; see No. 52,035, p. 284 ... 0. 4.0 52.036. - - idem, larger, 250 mm diameter, see No. 52,036 on p. 284 0. 6. 0 54,076. Top for Rotating Colour Discs, Figure, with flywheel and grip, without Colour Disc 0. 10. 0 54,078. Colour Disc with Rotating Apparatus, Figure 1. 5.0 The coloured sectors are on the back of the disc and are not visible in the illustration. 51,969. Cord Gearing for setting colour discs and the like into very rapid rotation, fitting Whirling Tables Nos. 51,949/51,968, cf. Fig. 51,969, p. 279; without Colour Disc or Whirling Table 1. 0.0 In addition to the Whirling Table and a Colour Disc being necessary for this collect inn, the larger Cord Pulley of Apparatus No. 51,975 is required, and this Apparatus should be ordered separately if not available. * 54,079. Transparent Colour Disc (Newton's) with 7 colours on glass, for objective projection, with device for rotating 1. 0.0 The colour disc gives a good white. Cl. 1365, * Can be used with Projection Apparatus. isei, 1364, taue. No. 54082. Spectrum, Colour Mixing, Spectrometers. 505 54 080. 1 : 6. 54081. 1:6. Spectrum Apparatus and Accessories, Spectrometers, Spectographs, etc. 54,080. Large diameter Precision Spectrometer, Figure, with rotary divided circle 255 mm The divided circle is graduated in Viz0 and has alidade and two microscopes for estimating to 1 . The telescopes, with 33,5 mm aperture, can be adjusted vertically. The entire instrument can be rotated about its vertical axis, has a symmetrical gap with comparison prism, reflecting eyepiece and an adjustable prism of 50 mm. 54.081. Spectrometer after Bunsen, Figure, with fixed divided circle 270 mm diameter _The circle is divided in Ye0, the vernier reading gives 10". The objectives have a focal length of 325 mm and aperture of 33,5 mm. The gap with comparison prism opens symmetrically to the right and left. The apparatus has a rotary table for taking a number of prisms. Two oculars (one after Gauss) and a prism pertain to the^ apparatus. The entire apparatus can be rotated about a vertical axis. 54.082. Polarisation Outfit for above, with two nicols and two position circles 100 mm diameter, graduated on silver, vernier for 1/lt>° and Babinet Compensator for elliptic polarisation £ s. d. 75. 0.0 45. 0.0 22. lit. d Cl. 1373, 1374. 506 Spectrum Apparatus. No. 54 083 — 54 083 B. 1:5. 54086. 1:5. Repeating Spectrometer, Figs. A and B, with two telescopes of 2(! nun aperture £ s. d. and 234 mm focal length, with Gauss Ocular, with concealed circle and arrangement, for carrying out goniometric measurements by Wollaston's method 41. 5.0 The circle is divided in '/40 on silver and permits of readings by a magnifying glass and two verniers to 2o". Fig. A shows the instrument set up for use as a spectrometer, and Fig. B for use as a goniometer. 54,084. - - idem, without concealed graduated circle or arrangement to permit of gonio- metric measurements being made by Wollaston's method 33. 0. o A Gauss Ocular is given in for goniometric measurements. Spectrometer after v. Lang, see Fig. 53,827, p. 482, practical school model for laboratories, with concealed circle and magnifier reading; also adaptable as goniometer, without prism 15. 0. 54.086. Wave Length Spectrometer with variable Deflection, Figure, especially adapted for rapid and accurate measurements 32. 10. o The apparatus has a <|iiadrilatcral prism which totally reflects and refracts the light. The stage is arranged to rotate so as to be able to determine the wave lengths of the spectrum-lines observed. The wave lengths are read direct on a spiral drum. Focal length of observing telescope and of the gap tuhe 2!).-J"> cm. aperture :il.:> nun. 54.087. - - i de m, with lengthened arm for the gap-tube in order to be able to place on it a Michelson Echelon Grating (No. 54,090) a Lummer-dehreke Plate (No. 51,0*9) "i a Fabry and Perot Air-plate (No. 54,091) 45. 0. d 54.088. Micrometer Ocular for above, for measuring t lie diameter of the Haidinger Intciiercnec- ring System when using the Fabry and Perot Interference Air-plate No. 51. (MM as an auxiliary to the Echelon grating and the Lummer-Gehroke Parallel Plate 8.15.0 (1. 1376, Diffraction Gratings: see Section "Diffraction of Light". 1377,771 No. 54 096. Spectrum Apparatus and Accessories. 507 54092. 1:8. 54 095. 1 : 6. 54.089. Interference Plate after Lummer-Gehrcke, Figure, in mount, for using ordinary spectroscopes as Interference Spectroscopes, for demonstrating the Zeeman effect, etc. ; also specially adapted for Spectrometer No. 54,087, for obtaining high resolving power 54.090. Echelon Grating after Michelson, Figure, for the same purpose £ s. d. 12. 10. 0 12. 10. 0 11. 5.0 23. 0.0 54.091. Interference Plate after Fabry and Perot, standard of approximately 10 mm air distance, for measuring wave lengths by utilising Haidinger's Interference Rings; can be used with Spectrometer No. 54,087, with quartz hollow cylinder of low temperature coefficient between the boundary plates 54.092. Spectrum Apparatus with a Rutherford Prism, Figure The observing telescope and gap-tube have an aperture of 30 mm and focal length of 312 mm. The telescope is a power 10 instrument; diameter of plate 180 mm; telescope focussed by micrometer screw; arc divided in '/u0 with vernier, in one piece with the alidade of the telescope, permitting a reading of 12", by which the position of the lines in the spectrum is determined. Gap with micro- meter screw and comparison prism. The dispersion from A — H2 is 14°. The two D-lines are at an angle of 1' 36" to each other; the fine nickel line should be plainly visible between these when the instrument is correctly focussed. 54.093. --the same apparatus, with arrangement for convenient reading of the scale parts 26. 0. 0 A reading tolescope is fixed above the observing telescope and parallel to the same. The former telescope has a right-angled prism at the end and brings to the vision of the observer by reflection the graduation of the divided arc and of the vernier. 54.094. Spectrum Apparatus, as No. 54,092, but smaller pattern; observing telescope with aperture of 27 mm and focal length of 230 mm, power 8; a gap-tube of the same dimen- sions; with brass plate on which both tubes are mounted, of 155 mm diameter; graduated arc divided in 1/6°, vernier giving 30" 18. 0. 0 54.095. Spectrum Apparatus, F i g u r e, same size as No. 54,092, but instead of having a Eutherford Prism is fitted with a 60° prism constmcted of extra heavy flint glass and with a dispersion of 7°. The position of the lines in the spectrum is in this case de- termined by a telescope with photographic scale instead of by divided circle. The observing tube can be adjusted by micrometer screw. Gap with micrometer screw and comparison prism 14. 0. 0 54.096. Spectrum Apparatus with observing telescope and gap-tube of 27 mm aperture and 230 mm focal length, with the scale telescope mounted on a brass plate 135 mm in diameter; observing tube without rack or micrometer screw; gap with micrometer screw and comparison prism 7. 10. 0 This apparatus is very efficient in spite of its low price; externally it resembles very closely Fig. 54,095. Cl. 5595, 5372, 6055, 1384. 508 Spectrum Apparatus. No. 54 097 — 54 100. 1 : 7. 54 101. 1 : 6. 54,097. School Spectrum Apparatus, Figure The apparatus has a 60" prism constructed of medium heavy flint glass and fitted on a brass plate 92 mm diameter on which is mounted the telescope, with scale. The observing telescope and gap tube are placed on the two arms, rotating on a trunnion, and situated underneath the plate. The arm carrying the observing telescope is movable and can be firmly clamped in any position in order to observe the spectrum conveniently. The observing telescope and gap tube have an aperture of 20 mm, a focal length of 150 mm, and a magnification of 5. The gap has a micrometer screw and, for the purposes of better demonstration, a Comparison Prism which can be switched out of operation. Dispersion 4". The stand has height adjustment. £ s. d 4. 10. 0 54,098. — the Prism same Apparatus, but without Telescope and Scale or Comparison 4. 0.0 Goniometers and Spectrum Apparatus for students' exercises, after Grimsehl (Ztschr. f. d. phys. u. chem. U. 17, 1904, p. 207), see No. 53,818, p. 481 2. 8. 0 54.099. Spectrum Apparatus for Chemical and Pharmaceutical Researches, F i g u r c, arranged for setting up horizontally and vertically 10. 0. 0 When the apparatus is set up vertically both the sunlight and flames tit various heights can be observed. A heavy flint glass prism (60°) is enclosed in a tightly fitting cap. 54.100. Spectrograph, F i g u r c, consisting of a Spectroscope combined with a Photographic Camera 13x18 cm ,12. 10. 0 The spectroscope contains 1 <|iiintuple direct-vision pri-m. 1 triple eollimator objective of 20 mm aperture, 1 single micrometer gup slider with divided drum. The camera r;m lie rotated in the vertical plane and a rack is provided tor sharp focussing. The ground gluss disc aud the dark slide can be displaced vertically so as to admit of ,"> exposures being made on one plute. The apparat us is specially suitable for investigating colour-sensitive plates and for teaching purposes. CI. 1385, 1387, 1388. 1388. No. 54110. Spectrum Apparatus. Zeenian Phenomenon. 509 54103,54108. 1:8. 54 110. 1 : 9. 54.101. Direct-vision Spectroscope after Janssen-Hofmann, Figure (Fr. phys. Techn. II, 2, Fig. 2818 [II, 904]) Observing telescope and gap-tube with 22 mm aperture, 182 mm focal length and approx. power 7. Gap with micrometer screw and comparison prism. On the middle cylindrical portion, in which the prism-system is fixed, a telescope with photographic scale is arranged laterally. The move- ment of the observing tube is carried out by a micrometer screw with a view to controlling the very extended spectrum, while focussing is carried out by rack and pinion. The apparatus is mounted on a stand having universal motion. Dispersion from A — H1, approx. 9°. 54.102. - - idem, with two prism-systems and twice the dispersion (approx. 18°) .... 54.103. Interference Spectroscope after Lummer-Gehrcke, Figure (Verhandl. d. Deutschen Physikal. Gesellschaft 9, 1907, p. 529), also adapted as an ordinary spectrum apparatus with low dispersion and, in conjunction with the necessary accessories, for demonstrating the Zeeman effect The resolving power of this apparatus is extraordinarily high — so great that '/too of the distance of the D-lines can be resolved. The apparatus has a simple gap, one ocular with cross wires, one plane parallel glass strip and a reflecting prism. It is for use as a low-dispersion spectrum apparatus. 54.104. Wollaston Prism, in Mount, for sliding over the ocular of the Spectroscope 54.105. Wollaston Prism with 1/t wave-length plate, in mount 54.106. Spectrum Tube with H or Hg 54.107. Spectrum Tube Stand with Condenser and Electromagnet for 6 volts, for demonstrating the Zeeman effect 54.108. — idem, with double Electromagnet, Figure, for the Zeeman transverse and longitudinal effect 54.109. Interference Spectroscope as No. 54,103, for use as a Spectrum Apparatus with strong dispersion ................................... The apparatus has a second flint glass prism and direct-vision prism body which can be switched into operation, simple gap, one Ramsden ocular of 28 mm and a similar one of 19 mm focal length with cross wires and plane parallel glass strip. 54.110. Grating Spectroscope for the Zeeman Phenomenon, after Weinhold, Figure, with a Eowland Plane Grating and an Electromagnet, for observing in a longitudinal direction and in a direction transverse to the lines of force ................ The apparatus is arranged in such manner that the observing telescope can be shifted over for observations with the right or left eye. The electromagnet can be rotated about its vertical axis and, at the positions in which the magnetic axis coincides with the axial direction of the collimator tube, or perpendicular to this, it can be clamped with a securing pin. If a mercury spectrum tube, fixed between the magnet poles, is illuminated by a spark-coil, it shows the characteristic green line of mercury in a simple manner as long as the magnet is unexcited, but an extended line is shown when (lie magnet is excited. In addition the observed line of the spectrum is polarised. In observing perpendicular to the lines of force three single lines result (a triplet) which are rendered the most plain when the S6narmont Prism, given in with the apparatus, is placed on the ocular which, acting as an analyser, shows two spectra which are brought above each other by rotating; two lines then appear in the deflected polarised part, and a single line in the unpolarised. In observing in the direction of the lines of force a doublet is produced consisting of two circular -polarised lines. £. s. d. 16. 0.0 20. 0.0 18. 0.0 1. 7. 0 2. 0.0 0. 7.0 5. 5. 0 10. 10.0 32. 0.0 60. 0. 0 Cl. 6050, 5533. 510 Spectrum Apparatus. N'o. 54111 — 54 113 A. 1:2. 54113B. 1:2. 54 112. 1 : 6. 54 117. 1 : 2. 54116. 1=4. 54 118. 1 : 2. 54 119. 1 : 4. 54.111. Spectroscope after Mousson, very simple (M. P., 9th. Edn., II, 1, Pig. 196) . . . The spectroscope has an adjustable stand, gap with comparison prism and micrometer screw, gap-tube with lens of 160 mm focal length, also an extra heavy flint glass prism. 54.112. -- idem, without comparison prism, Figure '2.16.0 £ s. d. 3. 0.0 54.113. School Spectroscope, F i g s. A and B, consisting of a Gap-tube with gap and Ions and two extensions, one with a direct-vision prism and a second with a Flint Glass Prism 54.114. Cap for above with aperture for containing reagent glasses, with 6 reagent glasses 54.115. Stand for No. 54,113 to enable the apparatus to be tilted 54.116. Students' Spectroscope, very simple pattern, Figure, with triple prism (direct- vision), non-adjustable gap, on wood stand for convenience of manipulation .... 54.117. Pocket Spectroscope with Diffraction Grating, Figure, showing hundreds of lines in the solar spectrum; the D line is split up A good imitation of a genuine Rowland Grating is used as Diffraction Grating for the instrument. 54.118. Pocket Spectroscope with Diffraction Grating and Reading Device, F i g u r <• A brilliantly illuminating arrow, visible above the spectrum, can be placed on a difinite line by means of a milled wheel. By means of a special lens, fitted alongside the eyepiece, tin- position of the arrow can be read off externally on a scale; the readings correspond to the momentary wave-lengths. fl. 13 idem, with wave-length scale 54.126. Universal Stand, for use with lS7os. 54,120/5, Figs. 54,123 B and C, with illuminating mirror, stage and clamp for the spectroscope, one absorption trough, one absorption tube. Price without Spectroscope I'm investigations on weakly absorbent solutions or on solids the spectroscope is placed verti- cally — see illustration. £ s. d. 5. 10. 0 2. 5.0 1. 13. 0 0. 12. 0 4. 15. 0 7. 10.0 8. 0.0 3. 5.0 Cl. 1396, 5951, 3802, 1400, 1401, 1398. 512 Accessories for Spectrum Apparatus. No. 54127 — 54131. 1:6. ~-^*B F 54 128. 1:5. 54 133. 1 : 5. 54 134. 1 : 2. 54.127. Double Gap with micrometer adjustment, Figure, for comparing the luminous £• »• <*• intensities of two spectra, for demonstrations 2. 8. 0 The colours of one spectrum are conducted through the gap by the aid of a total reflecting prism. : 54.128. Universal Stand for Spectrum experiments, Figure 3. 0. 0 The Stand serves for holding small glass troughs, spectrum tubes, the Delachanal and Mermet spark tubes, and as a holder for glass tubes having platinum lugs. 54.129. Small Glass Tube with platinum lugs. Price per 12 0. 6. 0 54.130. Stand for holding the small glass tubes (M. P. II, 1, Fig. 475 [216]) 0. 4. 0 54.131. Burner for Monochromatic light, after Terquem, Figure ' 1. 10. 0 54.132. Burner for monochromatic light, after Noack, Figure (Ztschr. z. Ford. d. phys. U., 2, p. 67) .' . 0. Hi. o 54.133. Breitenlohner's Spirit Lamp, Figure, with Bunsen burner attachment and safety tube, on tripod 0. 16. 0 Spirit Bunsen Burners, substitute for Gas Burners: see Nos. 51,214 and 51,216, p. 209. 54.134. Spirit Lamp, Figure, with adjustable holder for platinum wires, of brass ... 0.12.0 Bunsen Burners: see Nos. 51,184 et seq. 54.135. Spectrum Lamp for continuous Vapour Spectra, after Eder andValenta, with a rotating platinum wire net which plunges in the liquid (M. P. II, 1, Fig. 479), without plati- num net 5. 0. 0 The price of the platinum net (based on the current price of platinum) quoted on application. Cl. 5212, 3390, 1409, 1408, 1410, 3391. No. 54 144. Spectrum Lamps. 513 54136. 1:3. 54137. 1:12. 54 143. 1 : 8. 54139. 1:6. 54142. 1:5. 54144. 1:3. 51,130. Spectrum Lamp with angular pulveriser after Beckmann, Figure (Ztschr. f. phys. Chemie, 40, p. 470), with burner, rubber tubing and pinch-cock, especially for labo- ratory work 54.137. Large Spectrum Lamp for chemical pulverisation, after Beckmann, Figure, for demonstrating the influence of coloured flames on environment (Ztschr. f. phys. Chemie, 57, 1907, p. 641) 54.138. 7 Diaphragms for Relief Spectra (M. T. p. 187 [188]) * r>4,139. Lantern for objective Chemical Spectra, Figure (W. D. Fig. 295 [278]), for demon- strating the principal spectra by means of sets of Bengal Lights 54,140. Lantern with Nernst Lamp, after Grimsehl, for optical experiments (Sonderhefte d. Xtsehr. f. d. phys. u. chem. U. 1, p. 53), with lens mount, diaphragms, gap, etc. . . * r>4,141. Collimator Tube with Micrometer Gap after Grimsehl, on Stand, for demonstrating the spectrum objectively (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 209, Fig. 1C) 54.142. Mitscherlich's Apparatus, F i g u r e, with 8 glass tubes with platinum wicks, for permanent spectra 54.143. Revolving Device on Stand, Figure, for observing 6 spectra consecutively, con- sisting of six carbon rods impregnated with different salts t,144. Revolving Device for Arc Lamps, Figure, for rapidly alternating six carbon rods; to be used instead of the lower carbon of the projection arc lamp 50,922. 6 bored Carbons with Solid Carbons, the former filled with salts, for spectrum e ments (see No. 50,922, p. 171) * Can be used with Projection Apparatus. ci. Mil, 5928, 1362, 1412, £ s. d. 0. 12. 0 1.10.0 1. 4.0 1. 6.0 2.18.0 1. 4.0 1. 6.0 2. 10. 0 1. 0. 0 0. 9.0 5871, 1414. 33 514 Accessories for Spectrum Apparatus. No. 54145 — 54 145. 1 : 7. 54 146. 1 : 8. 54 147. 1 : 2. 54 149. 1 : 4. 54 150 — 54 154. 1 : 8. 54 155 — 54 159. 1 : 8. 54.145. Apparatus for investigating Metal Spectra by the aid of the spark intensified by the £• * Leyden Jar, Figure 1.12.0 There ;ire supplied with the apparatus metal points of copper, brass, iron, aluminium and German silver. For Condensers: see Electricity Section. 54.146. - - idem, simpler, Figure.... i 0. 16. 0 54.147. Spark Tube after Delachanel and Merniet (Fulgurator), Figure (W. u. E. phys. prakt., Fig. 189) 54.148. - - idem, with stand 54.149. — i d e m, after Vogel, Figure (M. P. 9th Edn., II, 1, Fig. 219 ) Sparking Pillars for Metal Spectra and Spark Tubes for Liquids, after Browning, combined with Condenser for intensifying the spark, Figure. List No. 54,150 54,151 54,152 54,153 54,154 For induction Coils with Spark Lengths of mm 60 100 150 200 LT.O £ 5.0.0 6.0.0 9.0.0 12.0.0 15.0.0 Sparking Pillars after Browning, Figure, as before, but witli device for inserting 2, 4, 6, 8, 10 — 20 condenser plates for intensifying the spark as desired. List No. 54,155 '54,156 54,157 54,158 54,159 For Induction ('oils with Spark Lengths of mm «»o 100 150 200 250 £ 7.0.0 8.0.0 11.0.0. 14.0.0 17.0.0 54,160. 2 Sheet Iron Electrodes for producing the Spectra of incandescent Vapours (M. T. Fig. 145) C'l. 1415,1416, 1417. 1418 o. ;•;. d 0. 12. 0 0.15.0 0. 4. 0 1419,3838, X.i. S4 174. Spark Tubes, Spectrum Tubes, Spectrum Lamps. 515 54173. 1:3. 54174A. 1:4. 54 168. 1 : 3. 54 172. 1 : 4. 54 174 B. 1:4. 54.161. Spectrum Tube after Geissler, Figure, thoroughly well constructed, with O, H, £ s. d. N, CO. CO2, H2O, Cl, HC1, Br, I, Cy, HOy, NO, NO2, Carburetted Hydrogen; Solids: S, Se, Hg or Hg2S each 0. 3. 6 54.162. Spectrum Tube, filled with argon (A) or helium (He) 0. 10. 0 54.163. Spectrum Tube with 2 cocks, Figure, for evacuating and filling automatically 0. 5.0 54.164. Stand for Spectrum Tubes, Figure 0. 18. 0 63,071. -- idem, simpler 0.10.0 54.165. - - idem, after Friedr. C. G. Miiller (M. T. Fig. 144) 0. 12. 0 54.167. Spectrum Tube, end-on pattern, filled with O, H, N, CO, CO2, H2O, Cl, HC1, Br, I, Cy, HCy, NO, NO2, NH3, SO2, SO3, H2S, SnCl2, etc each 0. 5.0 54.168. Spectrum Tube with Capillary, with Cylindrical Electrodes, Figure, for viewing cnd-ori and side-on from both sides, can be supplied filled with the same gases as No. 54,167 0.10/0 54.169. - - idem, filled with argon (A), helium (He) or a mixture of argon and helium | 0. 18. 0 54.172. Stand with Fine Motion for Spectrum Tubes, Figure, for concentric adjustment of the capillary with the spectrum apparatus, vertical fine motion by screw M, hori- zontal fine motion by lever H, vertical motion by lever V 2. 0. 0 54.173. Mercury Spectrum Lamp, Figure 0. 10. 0 This lamp generates an intense white light well adapted for optical purposes. It is worked by a not too small induction apparatus and requires no water cooling. The lamp is arranged so that only the cross-section of the capillary tube is utilised; the luminous source then shines as a small circular spot of great intensity. 54.174. Mercury Arc Lamp after Lummer-Straubel, Fig. A, with water box on adjustable stand, Fig. B 4. 0. 0 The lamp requires a pressure of 25 — 30 volts for working; even if it can stand a considerably higher voltage than this it is not advisable to go above 30 volts if the lamp lias to be durable. If it has only to be used for a very short time it will be sufficient simply to till the box witL water; if, however, it is intended to work it for some hours the water must be made to circulate. 54, 174 A. Spare Mercury Arc Lamp, Figure 1. 5. 0 Cl. 1421, 1422, 1421 >. 1423, 1425. 4820,4841,1424. 33* 516 Accessories for Spectrum Apparatus. No. 54 176 - 54 192/93. 1 : 5. 54 189. 1 : 3. 54 195. 2. 54 196. 1 : 4. Small Flasks with absorbent Liquids, with parallel walls, in case: List No. 54,176 54,177 54,178 Quantity 6 9 12 £ 0.10.0 0.15.0 1.0.0 54,179. Absorption Box with plane parallel detachable walls and Schulz Glass Block, F i- gure (M. P. 9th Edn., II, 1, Fig. 241; W. u. E. phys. Prakt., Fig. 250) 54.180. Absorption Box, rectangular form, Figure, with wide projecting bottom plate and loose cover; inside measurements: 55 x 35 x 10 mm 54.181. -- idem, U-shaped, Figure; inside measurements: 30 x 20 x 5 mm . . . . 54.182. -- idem, inside measurements: 50 x 20 x 5 mm 54.183. --idem, bottle-shaped, Figure; inside measurements : 20x4 mm Hollow Crystal Glass Cubes, Fig. 54,187, open on one side: List No. 54,184 54,185 54,186 54,187 54,188 External Size mm 30 40 50 60 80 £ 0.1.6 0.2.0 0.3.0 0.4.0 0.6.0 54.189. Absorption Box with lid cemented on and ground-in stopper, Figure, 40 X 40 X 10 mm 54.190. Double Absorption Box, Figure, for simultaneously observing two different liquids ; inside dimensions of each compartment 40 x 25 X 10 mm 54.191. Absorption Vessel, wedge-shaped, 150 x 4x 25 mm £ s. d. 0.18.0 0. 3.0 0. 2.0 0. 2.6 0. 2.0 0. 8. 0 0.12. 0 0. 12. 0 Prismatic Troughs, Figure, each pair similar. Combined these vessels form an absorption stratum with parallel walls in which, by moving the single troughs, liquid strata of different density can be rapidly produced. List No. 54,192 54,193 mm 100x40 150x50 Per pair £ 0. 12. 0 1. 0. 0 54.194. Absorption Vessel, spherical, for gases, on Stand with lateral opening (M. P., 9lh Kdn., II.. 1, Fig. 222) 1.10.0 54.195. Absorption Trough for filling with :> mm long, 35 mm wide, 10 mm deep 0. 8. 0 54, !<»*;. Stand for holding Absorption Boxes, Troughs, Preparations, etc., Figure, with arrangement for raising and lowering by hand and with micrometer. The objects art- placed between two spring clamps and can be conveniently set up or removed ... 1. 0.0 51,197. 3 Gelatine Plates for Absorption Kxpeiiments (M. T. p. 198) 0. 2. 0 5J.I9S. 3 Coloured Glass Plates for Absorption (Experiments (M. T. p. 198) | 0. •"•. 0 Cl. 1426,1428, 1429,299,1430,1432. 1433,1431.1434,1435. No. 54221. Absorption Vessels, Reagents. Reversal of Sodium Line. 517 54 214. 1 : 6. 54 217. 1 : 6. 54 199. 2 : 5. 54 203. 1 : 5. 54218. 4. 54221. 1 54.199. Coloured Plate with Coal-tar colours, for absorption experiments with transmitted £ s. d. light, Figure 0. 13. 0 The slab contains eight different colours and a dark and a light tint for each colour. As shown in illustration, white strips are free between the colours so that the absorption spectrum can be con- veniently compared with the pure spectrum. 54.200. - - idem, simpler, with only one tint for each colour; the single colours are sepa- rated by black strips 0. 6. 0 54.201. Absorption Colour Plate for absorption experiments with reflected light, with seven coloured cross strips 0. 4. 0 54.202. Crystal Plates showing absorption phenomena: Uranite, Chalcolite, Parisite, Zir- conium, Didymium Glass each £ 0. 6. 0 to 0. 10. 0 54.203. Preparations for Spectrum Experiments, in box, Figure, containing: 6 pairs rods of silver, platinum, aluminium, zinc, copper, iron; 12 small bottles with parallel walls, filled with absorbent liquids; 6 spectrum tubes; 10 small bottles with chlorides; 10 glass tubes with platinum lugs 4. 4. 0 Salts for Spectrum Experiments, chemically pure, in preparation glasses: List No. 54,204 54,205 54,206 54,207 54,208 54,209 54,210 Na K Li Ba Sr Ca Eb £ 0.0.6 0.0.6 0.0.6 0.0.6 0.0.6 0.0.6 0.1.0 54.214. 10 Reagents, Figure, in small bottles with ground-in stoppers, fitted in block for storing 0. 15. 0 54.215. --idem, 6 Reagents 0. 10. 0 54.216. Box with Salts and Small Bottles, of mahogany, containing 10 Salts in small flasks, and 14 small bottles for absorption phenomena 1. 16. 0 54.217. Box with Tubes, small Glass Vessels and Reagents, containing: 5 tubes of 2, 3, 10, 15, 20 cm length with ground end surfaces; a flat glass vessel with detachable parts; 2 glasses filled with NO2 and Iodine; 10 glasses filled with salts; 12 glasses for absorption phenomena; 10 glass tubes with platinum lugs 3.12.0 54.218. Collection of 18 Preparations, Figure, for Spectroscopic investigations, in glass vessels having platinum wires, as follows: Ba2Cl2 + 2H2O; CuCl2 + 2H2O; CsCl; CaCl, +6H20;KaCl;In2Cl6;LiCl; XaCl; PbCl2; BbCl; SrCla + 6H2O; T1C1; Se; ZnCl2; TeCl^ and solutions of Di (NO3)3; KaMnO4; Er (NO3)3, in box 2. 4. 0 54.220. Apparatus for Reversal of the Sodium Line, after Bunsen (W. D. Fig. 297 [280]; M. P., 9th Edn., II, 1, Fig. 234) 0. 18. 0 54.221. - - idem, after Weinhold, Figure (W. D. p. 408 [375]), 1 Teclu and 1 Bunsen Burner on one base, and one asbestos slab 0. 16. 0 Cl. 3633,1436, 1437, 1438, 3302, 1440. 518 Accessories for Spectrum Apparatus. Fluorescence. Phosphorescence. No. 54 222 — 54 222. 1: 15. SOLAR -SPECTRUM. A a B C D El) F m n TO 3D 4* :n «o in so K limiliiiiliimlmilfiiilfltifiifiiniMl HO 170 1M 140 ISO 1SQ 1/0 ' inlimlliHlimliiuhtithiti Max Kohl Chemnitz. 54231. 1 : 11. 54.222. Apparatus for reversing the Sodium Line after Frankland, Figure (M. P., II, 1, £• s. d. Figs. 543 and 544 [231]), with platinum spoon and wire net 1.10. o 54.223. Sodium Tube for Reversing the Sodium Lines of refractory glass, evacuated with H 0. 10. 0 54.224. - - idem, with three bulbs 0. 10. 0 * 54,225. Bunsen-Burner with Pan and Sheet-iron Cylinder, after Grimsehl, for reversing the , sodium line, for objective demonstration (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 2. Fig. 1 [B] and Fig. 2) 0. 14. 0 * 54,226. Stand with illuminating Tube for reversing the strontium line, after Grimsehl, for objective demonstration (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 211, Fig. 3 [B]) 0. 16. 0 54.227. Table of Spectra after Kirchoff and Bunsen, containing the solar spectrum and the spectra of K, Eb, Cs, Tl, Na, Li, Ca, Sr, Ba 0. 7. 0 54.228. - - idem, containing the spectra of In, C, Bo, Mn, Pb, Cu, Co, Ni, Fe .... 0. 7. 0 54.229. Star Spectra Table after Vogel, containing the spectra of Sirius, ft Lyrae, Sun, B. D. 34° 4001, new star in Cygnus, a Orionis, Schjell. 152, and Carburetted Hydrogen Spec- trum for comparison 0. 7. 0 54.230. - - idem, containing the spectra of a nebula, of Uranus, of a comet, of carburet ted hydrogen for comparison, of the Sun's limb and illustration of spectrum of the Sun's limb with strong dispersion (displacement of lines) 0. 7. 0 54.231. Solar Spectrum, Figure, painted on linen, with frame, very pretty pattern . . 3.10.0 54.232. - - idem, with wood rods for rolling up, as Fig. 52,227, p. 36 ......... 3. 0. 0 * 54,233. -- idem, transparent, coloured 1.0.0 Fluorescence. 54.234. 3 Cubes of fluorspar, uranium and didymium glass, fluorescing blue, green and red respectively, 13 mm side, in box 1.16. 0 54.235. Cube of Fluorspar, fluorescing blue, 13 mm side 1. 0.0 54.236. - - of uranium glass, fluorescing green, 30 mm side 0. -. o 54.237. -- idem, 50mm side 0. 1. (i 54.238. - - of Didymium Glass, fluorescing red, 13 mm side 0. 12. o 54.239. Holder for Fluorescent Cubes, Figure, adjustable, with mount 0.18.0 When ordering kindly sliitc si/.c of rube to be inserted. 54.240. Uranium Glass Plate, 150 x 60 x 8 mm 0. :>. u 54.241. -- i d e m, 300x60x8 mm 0. !<>. o 54.242. Collection for Fluorescence Experiments, Figure, consist in.-: of 4 hollow glass cubes for liquids, rranium glass plate. Cranium glass cube, Didymium glass and fluor- spar, also condenser lens on stand 3.10.0 * t'iiu be used with Projection Ap|Ki';itn- Cl. 1441, 14»2 No. 54257. Reversal of Sodium Line. Spectrum Tables. Fluorescence. Phosphorescence. 519 54 239. 1 : 4. 54 242. 1 : 7. 54 244. 1 : 6. 54 255/57. 1 : 3 Collection of Fluorescent Liquids, Fig. 54,244, named, in wood frame with covers: List No. 54,243 54,244 54,245 54,243 6 8 10 12 solutions £ 0. 12. 0 0. 16. 0 1. 0. 0 1. 4. 0 54,247. Fluorescent Liquids for filling troughs 100 ccm Quartz Lenses, bi-convex, radius of curvature 150 or 300 mm: List No. 54,248 54,249 54,250 Diameter mm 40 50 60 £ 0.12.0 1.0.0 1.10.0 Geissler Tubes with Fluorescence Phenomena: see Section "Electricity". 54.251. Apparatus for Demonstrating the Fluorescence Spectrum of the Electric Light, after Stokes (M. P., 9lh Edn., II, 1, Fig. 250), consisting of 2 quartz prisms of 30 mm side, ground perpendicular to optical axis, two sides polished; 1 quartz lens 40 mm diameter, IlO mm focal length, bi-convex ; and 1 Uranium glass plate 150 x 60 x 8 mm, on stand 54.252. Violet Glass Plate 150 /. 150 mm, for Stokes's Experiment (M. P., 9th Edn., II, 1, p. 360) 54.253. Paper Strip prepared with barium platino -cyanide, 6 x 4 cm 54.254. Fluorescent Portfolio, with barium platino-cyanide Writing, in portfolio of blue and yellow glass Phosphorescence. Phosphorescent Substances, in case, Figure: List No. £ 54,255 3 0.5.0 54,256 54,257 5 7 substances 0. 7. 0 0. 10. 0 £ s. d. 0. 2. 6 8. 0. 0 0. 6. 0 0. 5. 0 0. 5. 0 Cl. 5215, 1443, 1444, 1445. 520 Phosphorescence. Photography. No. 54 258 — 54 258 B. 1:4. 54 258 A. 1:4. 54259. 1:8. 54 261. 1 : 6. 54 260. 1 : 7. 54.258. Case with 6 Phosphorescent Substances, shown open in Fig. A, and closed in Fig. B The case contains six small tlat glass tubes sealed up and containing pulverulent substances of different colours v. hick phosphoresce. In the lid there is a small wood slab let in under glass which :-; coated with a paint which shines a brilliant violet. 54.259. 7 Phosphorescent Substances, in eye tube, Figure. The back wall can be let down 54.260. NEW. Phosphoroscope after Lenard, F i g u r e,1 adapted for single experiments and for demonstration purposes (Hausser, Ztschr. f. Instrkd. 30, 1910, p. 278), with a pre- paration holder with 6 preparations, a trough with quartz lid for powdery substances, and a pair of tongs for holding any object; with 110 volt Direct Current Electric Motor, tachometer and motor interrupter The phosphorescent body is illuminated by an electric spark generated from an induction coil of 10 — 20 cm stroke between zinc electrodes, these electrodes being very rich in light exciting ultra- violet phosphorescence. The duration between lighting and observation is quite small. The apparatus is used when demonstrating from the side illustrated, and in individual experiments from the opposite side. 54.261. Phosphoroscope after Becquerel, Figure (M. P., II, 1, Figs. 590—592 [253]), on firm stand 54.262. - idem, large pattern, Figure, on cast-iron stand with toothed wheel gearing 52,046. Phosphoroscope arranged to fit Whirling Table: see Fig. 52,046, p. 284 54,263. Phosphorescent Paint (Balmain's) can be used in conjunction with water or oil colour. Per half-kilogramme Photography. 54,261. Folding Camera, Figure, for plates and films 9 x 12 cm, aluminium body covered fine leather, with double bottom extension, thus allowing the hack lens alone to be used. Objective adjustable laterally and vertically; three metal dark slides and intro- duction to photography. Price with Extra-rapid Aplanat The objective has -.n iris diaphragm and shutter for time photographs of any dur.it ion and in stantaneous exposures from '/too to 1 second. 'Ihe apparatus has a leather bellows, is fitted with a good finder and is arranged for vertical and horizontal pictures. The picture can 1 e f.>russed either by the scale or on the ground glass screen. Outside dimensions approx. 15.5 x 3.8 x 11.5 cm. For Stands see Nos. 54 288 and 54 289. £ s. d. 0.12.0 1. 0.0 IS. 0. 0 6. 0.0 20. 0. 0 2. 0.0 o. 15.0 5. 10. Cl. 1446, 1447, 3843, 1448, 5450. No. 54272. Phosphorescence. Photographic Apparatus. 521 54 262. 1 : 6. 54 264. 1 : 3. 54 269. 1 : 3. 54 272. 1 : 5. 54.265. Folding Camera exactly as No. 54,264, with Zeiss Double Amatar 1 : 6.8 .... 54.266. --idem, with Zeiss Double Protar 1 : 6.3 54.267. Film Pack Slide for Apparatus Nos. 54,264 — 54,266 54.268. Cow Hide Bag 54.269. Stereoscopic Camera, Figure, for taking sterescopic pictures and ordinary pictures (Panorama form), body of mahogany, leather covered, with triple bottom extension, objective adjustable vertically and laterally, 3 metal dark slides and instructions, with Extra Rapid Aplanats The objective has iris diaphragm, shutter for any time exposures and for instantaneous exposures from 1 to Vsso111 second. The apparatus has a leather bellows, is fitted with a finder and arranged for vertical or horizontal portrait.?. Focussing can either be carried out by the scale or on the ground glas* screen. External dimensions approximately, 18.5 x 5.5 x 13cm. For Stands, see Nos. 54,288 and 54,289. 54.270. - - idem, with Zeiss Double Amatars, 1 : 6.8 54.271. Cow Hide Bag 54,272. Scholars' Stand Camere, Figure, for plates 9x 12 cm, walnut body with long calico bellows, shutter for instantaneous and time exposures, for vertical or horizontal pictures, with three double dark slides, stand in two parts, and Periscopic Aplanat and revolving diaphragm £ s. d. 10. 5.0 13. 0.0 0. 8. 0 0. 14. 0 10. o. 19. 10. a o. 15. a 1. 15. 0 Cl. 1449, 5948, 5946, 5945. 522 Photography. Eye and Vision. NIL .14273 — 54 2S6. 1 : 4. 54274. 1:6. 54 290. 1 : 5. 54.273. Stand Camera, cf. Fig. 54,274, for plates 9x 12 cm, polished mahogany body, calico bellows with leather edges, conical and rotary; objective board having height and lateral adjustment; with plummet, spirit level, 'three double dark slides; with Extra Rapid Aplanat, iris diaphragm, Objective Shutter for time and instantaneous exposures, and tripod stand 54.274. --idem, Figure, for plates 13 X 18 cm 54.275. --idem, cf. Fig. 54,274, for plates 18 X 24 cm 54.276. --idem, cf. Fig. 54,274, for plates 24 X 30 cm 54.277. Bags of gray sail-cloth, can' also be carried as a knapsack. For Apparatus of plate-size 9x12 13 x 18 18 X 24 24 x 30 £ 0. 10. 0 0. 10. 0 0. 12. 0 0. 18. 0 Photographic Outfits, containing everything necessary for finishing photographs: List No." 54,278 54,279 54,280 54,281 For Cameras of plate-size 9 X 12 13 x 18 18 X 24 24 x 30 cm £ 0.9.0 0.15.0 1.10.0 2.6.0 The outfit consists of one dark room lamp, 12 plates, 1 packet Celloidin paper, 25 mounts, deve- loper, fixing bath, toning and fixing bath, papier mache dish, enamel dish, glass dish, glass measure, printing frame, mountant, brush, and instructions. Supplementary Outfits for Photography: List No. 54,282 54,283 54,284 54,285 For Cameras of plate-size 9x12 13x18 18x24 24x30 cm £ 0.10.0 0.12.0 0.14.0 0.16.0 Glass funnel, dropping bottle, plate grips for small plates, plate lifter, small brush, drying clips, draining rack, trimming glass, trimming springs, glossing slab, squeegee, flaslilight bag, flashlight powder, filter paper. 54,286. Magnesium Lamp with clockwork, Figure The clockwork runs 6 — 8 minutes and can be released and stopped by a lever. 54.287. S^pare Magnesium Tape 54.288. Tripod Stand for Apparatus Nos. 54,264 — 54,270, of ash, brass bound 54.289. Tubular Stand of brass, in five parts; length folded up 36 centimetres For Dark-room Fittings see pp. 79 — 82. The Eye and Phenomena of Vision. 54.290. Model of the Eye, after Bock, Figure, 80 nun diameter 54.291. - - larger, 130 mm diameter 54.292. Ophthalmotrope after Knapp, Figure, for demonstrating the motions of the eye and the action of the single musi-le* concerned therein £. s. d. 4. 0.0 4. .12. d 6. 4.0 9. 10. 0 1. 4.0 0. 1.6 1. 0. 0 0. 14. 0 0.10. 0 0. 12. 0 J. 8.0 I'l. 1472, ,W47. 1477. No. 54301. Photographic Apparatus. Models of Eyes. 523 54 298. 1 : 14. 54 299. 1 : 6. 54 301. 1 : 10. 54.293. Device for receiving an Ox's Eye, Figure, with small stand for the eye lens (W. D. £ s. d. Fig. 300—302 [283—285]) , 0. 6. 0 54.294. Optical Eye after Kiihne, Figure, for showing the part of the rays in the eye at a magnification of 10 times, myopia and presbyopia, Schemer's experiment, the path of the luminous rays after operation for cataract, astigmatism and accommodation of the eye. The trough is arranged for filling with a fluorescent liquid 5. 10. 0 Instructions for use are supplied with the Apparatus. 54.295. Water Chamber after Friedr. C. G. Miiller (M. T. Fig. 147) 1. 0. 0 54.296. Optical Eye after Grimsehl, arranged for filling with water, with diaphragm for the insertion of spectacle lenses. The variations in magnitude occurring in a short-sighted or long-sighted eye when a spectacle lens is inserted can be measured 1. 18. 0 54.297. Glow-lamp Filament, for use as an illuminating object to the preceding Apparatus 2. 0. 0 54.298. NEW. Optical Eye after Lichtenecker, Figure, with adjustable iris diaphragm, movable retina screen, diaphragm tube for shielding disturbing light, a second screen, with handle, in order to enable the position of a retina to be shown rapidly in the short- sighted or long-sighted eye; a convex lens and a concave lens with handle, and a piece of plaster showing the aspect of the interior of the eye 4. 10. 0 54.299. Optical Eye, Figure, with two spectacle lenses for explaining their action . . 1.16.0 Lens Apparatus after Dr. Zwick, see Nos. 53,924 — 53,928, pp. 496 and 497, for explaining myopia and presbyopia and the path of the rays in the eye, with lenses 50 mm diameter, for showing the action of lenses in general and of the camera obscura. 54.300. 30 Drawings for showing the blind spot, Figure, after Weinhold (W. D. Fig. 303 [286]) 0. 1.6 54.301 . Astigmatic Test Card after Dr. .Frankel, Figure, for ophthalmologists and schools, for quickly determining astigmatism 0. 2. 0 CI. 1478, 1479, 1480, 1482, 5426,5591, 1483. 524 Eye and Phenomena of Vision. No. 54 302 - 54 303. 1 : 9. 54304. 1 : 11. 54305. 1:5. 54 306. 1 : 5. 54 307. 1 : 6. 54.302. Device after Steinhauser, for Schemer's experiment (M. P., II, 1, Fig. 263 [359]) . 54.303. Apparatus for explaining the plastic Vision of both Eyes and of the Stereoscope, Figure The distance apart of the two telescopes is variable as is also the place at which the two spheres are set up. 54.304. Wheatstone's Mirror Stereoscope, with three pairs of drawings, Figure (M. P., II, 1, Figs. 276 and 277 [377]) 54.305. Stereoscope after Brewster, of mahogany, with movable mirror, Figure. . . . 54.306. - - idem, with variable ocular distance, Figure 54.307. Stereoscope, mounted open, Figure, of polished mahogany Revolving Stereoscope Apparatus, for rapidly changing the images, with variable ocular distance: List No. 54,308 54,309 Arranged for 25 50 views Without Views £ 2. 2. 0 2. 10. 0 54.310. Stereoscopic Views on paper Each 54.311. 12 Demonstrations of Stereoscopic Lustre, after Martius-Matzdorf 54.312. 36 Stereoscopic Drawings after Martius-Matzdorf, for demonstrating the overlapping of the images, the emulation of the visual fields, the artificially produced movement of the single images, the spatial vision (images of the better-known crystalline forms). the occurrence of stereoscopic lustre from the surface of image (e. g., in reproductions) 54.313. 12 Stereoscopic Views of the Firmament from excellent photographs by Prof. Max Wolf (Heidelburg). First series of 12 plates with explanatory text, in portfolio . . The motions of planets and comets and the motion of the fixed stars can be rendered quite comprehensive by the views. The photographs of the moon's landscape are shown in such great relief that the height of the mountains and depth of the valleys can be gauged. 54.315. Stereoscopic View (Girl's Head) on glass, after Ives, for explaining the spatial vision of both eyes, Figure A grating having black lines is set up in front of the parallax stcrt-ogram which is formed of perpendicular lines. The stereogram consists of two images composed of lines; the lines pertain alter- nately to an image for the left and for the right eye. Kaeh eye sees its view through the spaces of tin- grating and the result is a plastic image. 54.316. -- idem, with view of moon, specially adapted for also introducing pgeudoacopic vision. When the right eye assumes the position intended for the left and vice versa the moon appears as a hollow sphere £ s. (1. 0. G. 0 1.12. 0 1. 2. (l 0. 5. 0 0. IT). 0 0. 5.0 0. 0.6 0. 4.0 0. 8.0 0. 8.0 1.10.0 1.10.0 CM. 3395, 6094, 1484. 1485, I486. No. 54 322. Stereoscopy. Plastic Vision. Stroboscopy. 525 54318. 1:8. 54 315. 54 320. 2 : 5. 54 322. 1 : 5. 54.317. Schroeder's Step View, as diapositive (W. D. Fig. 312 A [295 A]) for demonstrating the impression of raised and deepened relief 54.318. Pasteboard Model of the Shroeder Step View, Figure, for facilitating the perception of the different impressions of relief * 54,319. Apparatus for imitating the Irradiation of the Moon's Crescent, Figure (W. D., Fig. 311 [294]) * 54,320. 2 Lantern Slides for demonstrating Irradiation, after Plateau, Figure (M. P., II, 1, Fig. 291 [388 and 389]) 54.321. Disc with sectors cut out, for showing the duration of luminous impression in the eye; for the Whiiling Table (W. D. p. 416) 54.322. Stroboscopic Disc, Figure (M. P., II, 1, Fig. 292 [393]) Rotating Mirrors: see p. 431. .").'). 179. Stroboscopic Drum (cylinder), see Fig. 53,179, p. 417, with 18 Quincke Wave Strips 52,019. - - idem, fitting the Whirling Table: see No. 52,019, p. 283 51'. (120. Strips alone, 18 in all, with description: see No. 52,020 on p. 283 * Can be used with the Projection Apparatus. Cl. 3683, 5516, 3397, U88. £ s. d. 0. 1.6 0. 4.0 0. 8.0 0. 3.0 0. 6.0 0. 18. 0 0. 18. 0 0.14.0 0. 6.0 343, 526 Eye and Phenomena of Vision. No. 54323 — 54326. 54323. 1: 12. 54327. 1:4. 54324. 1 : 4. 54325. 54328. 1:4. £ s. d. 53.302. Stroboscopic Disc after Topler, with clockwork drive, see Fig. 53,302, p. 432 ... 3. 0. 0 53.303. - - i d e m, for hand drive, see No. 53,303, p. 432 2. 0. 0 54,323. Stroboscope after Anschiitz, large pattern, Figure, with 10 rows of views ... 2. 0. 0 * 54,324. Stroboscope, Figure, for the Projection Lantern, with 1 disc (W. D. Fig. 304 [287]) 1. 0. 0 * 54,325. 3 Extra Discs for above, Figure, each £ 0. 2 0 0. 6. 0 * 54,326. Projection Stroboscope, Figure, with 2 discs, showing dancers .1. 4.0 * 51,067. Cinematograph, sec Fig. 51,067, p. 185 . . . . : 7. 10. 0 * 51,068. Films for Cinematographs: 16, 24, 32, 48 m long: see No. 51,068, p. 186 per metre length 0. 1. 6 60,642. Lens Disc after Boys for the Stroboscopic analysis of spark discharges : see Fig. 60,642, p. 837 4. 0.0 * 54,327. Anorthoscope for the Projection Lantern, Figure (Fr. Phys. Techn. II, 2, Fig. 3362 [II, Fig. 881]), with 4 discs with distorted images, which on rotating appear in tin- correct form but five times as large •!.(>.(> * 54,328. Apparatus for Optical Fatigue and the successive Colour-contrast, Figure (Fr. phys. Techn. II, 2, Fig. 3497 [II, Fig. 894]) 0. . S4 379. Camera obscura, Camera lucida. Magnifying Glasses. Microscope. Telescope. 531 54 374. 1 : 6. 54 371. 1 = 4. 54 372. 1 : 4. 54 379. 1 : 8. 54.366. Model of the Compound Microscope, Figure, constructed open, on wood base, the £ 8. d. path of ray being indicated 0. 15. 0 54.367. Model of the Galilean Telescope, Figure, constructed open 0. 8. 0 54.368. Model of the Astronomical Telescope, Figure, constructed open 0. 10. 0 54.369. Model of the Terrestrial Telescope, Figure, constructed open . 0. 16. 0 54.370. Model of Newton's Reflecting Telescope, Figure 0.18.0 54.371. Model of the Brachio-Telescope, Figure, constructed open • 1. 0. 0 54.372. Model of a Meridian Circle, of wood, Figure, with metal circle and indices, dia- meter of circles 120 mm 2. 14. 0 54.373. - - idem, of metal 5. 8. 0 54.374. Small Weinhold Optical Bench, Figure, for Explaining the Microscope, the Astro- nomical, Terrestrial and Galilean Telescopes, on pillar base; lenses 20 mm diameter, objective 70 mm; all lenses mounted in metal (W. D. Fig. 317 [300]) 1. 6. 0 Perforated Cylindrical Pillar: see Nos. 53,688 and 53,689; Gas Burner: see No. 53,681a; Paraffin Burner: see No. 53,684a; Ligroin Lamps: see No. 54,375. ">4. :;;.">. 3 Ligroin Lamps, arranged close together (W. D. p. 440), cf. Fig. 53,626 0. 6. 0 54.376. Optical Bench as No. 54,374, without pillar, on two short legs 1. 2. 0 54.377. --idem, on pillar base, but with larger lenses (40 mm) and an objective 120 mm diameter 2. 0. 0 54.378. Small Mirror on Stand and Total Reflection Prism on Sliding Blocks, for demonstrating the Herschel Telescope and the Newton Reflecting Telescope; for use with Optical Bench No. 54,374 or 54,377 (W. D. Fig. 320A and B [302A and B]) 0. 16. 0 54,370. Small Optical Bench with Glass Box, Figure, for demonstrating the path of nivs in. lenses, telescopes of different systems and in microscopes, with 11 lenses and 5 dia- phragms 7. 0. 0 Cl. 4528, 1522, 1521, 5316. 34* 532 Optical Instruments. Microscopes. No. 54380 — 54 382. 1 : 5. 54386, 54 386 f, 54 386 h. 1 : 5. 54 380. 1 : 5. 53 385. 1 = 6. 54,380. Model Theodolite, Figure, of metal, with level and cross-wires, can be used as a £ * «'• sight. The circles are divided in 360° and verniers permit of reading to Vio"1 °. Circle rotary for repetition, telescope without lenses i 4. 0. o 54,381. --idem, with Telescope, ocular movable by rack and pinion 54,382. --idem, Figure, with Telescope, Ocular Prism, and Sun Glass, for astronomic:*! observations (M. T. p. 26) 54.383. Stand for Model Theodolites Nos. 54,380/2 (W. D. Fig. 29), with- stem screw . . . 54.384. Carrying Case for Model Theodolites Nos. 54,380/2, for use in field work .... 54.385. Model Theodolite for Students' Exercises, Figure, with Telescope and Carrying Case, Folding Stand, Measuring Chain, and folding Measuring Stave 3 in long. The horizontal circle is 10 cm diameter and the altitudinal circle !l.5 cm 54.386. Theodolite, cf. Figure, horizontal circle 120 mm diameter divided in 1/2°, verniers giving 1', graduated on brass, silvered, uncovered. Reading by means of hand glass; telescope 200mm focal length, power 20, inclusive of bolts and stand witli tribrach . Extras: (a) for repetition £ 2.0.0; (b) for telescope a\is Imvinji clamp and fine adjustment £ 1.5.0: (<•) for rotary "magnifying glasses £ 1.4.0: (d) levelling bubble i 1.4.0: (e) for graduating the horizontal circle on (ieriiian silver £ 0.15.0: (f) for spherical stand \vitli tribrach instead of the bolting stand £ 0.10.0; (g) for graduating the horizontal circle on silver in 1/3°, verniers giving 30" covered, \vitli rotary magnifiers, £ 4.5.0; (h) for dividing the altitudinal circle in Vz0 on brass and silvering, verniers Diving 1', £ 3.0.0: (i) for telescopes arranged for throwing back, with adjustable carrier £ 1. 7. 0. 6. 0.0 6.12.0 1.10.0 1 . 6. 0 8. 0.0 12.10.0 Cl. 1528. 1527,8098, 1529. No 54389. Theodolites. Microscopes. 533 54 387. 1 = 5. 54 388. 1 : 3. 54,387. Repeating Theodolite, Figure, with drop-screw, for distance measurements; telescope arranged for tunneling and canting back, with steel axes, rotary magnifiers; Horizontal Circle concealed by glass, and silver limb; Striding Level, round pattern Level on vernier circle; horizontal circle 140 mm diameter divided in l/3°, verniers giving 20"; altitudinal circle 120 mm diameter in Vs0* on silver, concealed, with verniers inserted giving 30", with alidade level and micrometer screw; telescope 250 mm focal length, power 25; with carrying case, shoulder straps and spherical stand The telescope has an orthoscopic ocular and a range of 7 km; it is provided with clamp and fine adjustment, being arranged for measuring distances. Extra Prices: (a) for levelling bubble on telescope £ 1. 7. 0 (b) „ Transit Level £ 1. 14. 0. Particulars and prices of Larger Theodolites on application. Microscopes. 54.388. Large Microscope, Stand I, Figure, with socket for tilting down; round, rotary and centering stage, coarse and fine tube focussing, millimetre graduation on draw tube; large illuminating device, after Abbe; Abbe Indicating Apparatus; optical outfit for 14 — 1400 diameters, and case .The coarse tube focussing is by rack and pinion, the fine by worm and worm wheel; a complete turn of the worm corresponds to raising or lowering the tube by 0.1 mm. The optical outfit consists of 1 micrometer ocular, 4 Huyghenian oculars, 3 achromatic objectives, 1 homogeneous oil-immersion objective and triple nose-piece. 54.389. - - idem, with fixed stage, simple illuminating apparatus and simple optical equip- ment, for 20 — 1400 diameters, without indicating apparatus £ s. d. 35.0.0 30. 0. 0 24.0.0 For Model Microscopes: see previous section. Cl. 1530, 5936. 534 Microscopes. No. 54 390 — 54 390. 1 : 3. 54 392. 1 : 3. £ s. d. 21. 0. o 19. 5.0 54.390. Large Microscope, Stand la, Figure, with canting joint, with round centering stage, coarse and fine tube focussing, millimetre graduation on draw tube; large Abbe Illuminating Apparatus; with iris diaphragm; optical outfit for 26 — 1400 diameters, together with box The Optical outfit comprises 4 Huyghenian oculars, 3 achromatic objectives, 1 homogeneous oil- immersion, and triple nose-piece. 54.391. - - idem, with fixed stage, simple illuminating Apparatus and simple Optical Out- fit for 60 — 800 diametors The optical Outfit is correspondingly simpler. The coarse tube focussing is effected by rack and pinion, and the fine by a low-pitch micrometer screw. 54.392. Large Microscope, Stand B, Figure, with tilting joint, large round centering stage, coarse and fine tube focussing, millimetre graduation on draw lube, large Abbe Illumi- nating Apparatus, Optical Outfit for 60 — 1400 diameters, together with box .... The coarse tube focussing is by rack and pinion and the fine by a worm and worm wheel. Tne optical outfit comprises 2 achromatic objectives, one homogeneous oil-immersion objective. 1 triple in ise-piece and 3 Huyghenian oculars. 54.393. - - id em, with Abbe Illuminating Apparatus of smaller pattern, arranged for raising and lowering 18. 54.394. Large Microscope, Stand Ic, Figure, with tilting joint, with rectangular fixed stage, base and pillar in one pieee, coarse and fine tube focussing, millimetre gradual ion on draw tube, Abbe Illuminating Apparatus with iris diaphragm, Optical Outfit for 26 — 1400 diameters, together with box 17. The coarsi1 tube fnriii-siiii;- i< i-H'rcted by rack anil pinion. Mini the fine by low-pitch micromi-ti-r scrrw. The Optical Outfit comprises H achromatic objectives, 1 homogeneous oil-immersion, 1 triple revolving nose-piece and 3 Huygheniao oculars. 54,39."). - i d e m, with simple Illuminating Apparatus and simpler Optical Outfit for 60 to 800 diameters 1.",. 10. o 21. 5.0 0.0 7. o.O n. 51137, 5941. No. 54 401. Microscopes. 535 54 394. 1 : 3. 54 396. 1 : 3. 54400. 1:3. 54.396. Medium Microscope, Stand Ha, Figure, with joint for tilting, large rectangular fixed stage, coarse and fine tube focussing, millimetre graduation on draw tube, Abbe Illuminating Apparatus with iris diaphragm, Optical Outfit for 26 — 1400 diameters, together with box The coarse tube focussing is effected by rack and pinion, and the fine by low-pitch micrometer screw. The Optical Outfit comprises 3 achromatic objectives, 1 homogeneous oil-immersion, 1 triple revolving nose-piece and 3 Huyghenian oculars. 54.397. - - idem, with simple Illuminating Apparatus and simpler Optical Outfit for 60 to 800 diameters 54.398. Medium Microscope, Stand C, cf. Fig. 54,392, with joint for tilting, rectangiilar fixed stage, coarse and fine tube focussing, millimetre graduation on draw tube, Abbe Illu- minating Apparatus, Optical Outfit for 60 — 1400 diameters, together with box . . . The coarse tube focussing is effected by rack and pinion, and the fine by worm and worm wheel. The Optical Outfit comprises 2 achromatic objectives, 1 homogenous oil-immersion, 1 triple revolving nose-piece, and 3 Huyghenian oculars. 54.399. - - idem, with simple Illuminating Apparatus with iris diaphragm, and simpler Optical Outfit, for 60 — 800 diameters 54.400. Medium Microscope, Stand lid, Figure, with joint for tilting, large rectangular fixed stage, coarse and fine tube focussing, millimetre graduation on draw tube, Abbe Illuminating Apparatus with iris diaphragm, can be f ocussed under the stage ; Optical Outfit for 60 — 1400 diameters, and box The coarse tube focussing is effected by rack and pinion, and the fine by small-pitch micro- meter screw. The Optical Outfit comprises 2 achromatic objectives, 1 homogeneous oil-immersion objective, 1 triple nose-piece and 3 Huyghenian oculars. 54,401. -- idem, with simple Illuminating Apparatus, and simpler Optical Outfit for 60—730 diameters . 12. 0. 0 £ s. d. 18. 5.0 16. 5.0 16. 10. 0 15. 0.0 15. O.'O Cl. 5940, 5935, 5939. 536 Microscopes and Auxiliary Apparatus. No. 54 402 - 54402. 1 : 3. 54407. 1:3,5. 54409. 1:4. 54.402. Medium Microscope, Stand III, Figure, not tiltable, with rectangular fixed stage, coarse and fine tube focussing, millimetre graduation on draw tube, Abbe Illuminating Apparatus, with iris diaphragm; Optical Outfit for 60 — 1000 diameters, together with box The coarse tube focussing is effected by rack and pinion, and the fine by micrometer screw. The Optical Outfit comprises 2 achromatic objectives, 1 homogeneous oil-immersion objective, 1 triple revolving nose-piece and 2 Huyghenian oculars. 54.403. - - idem, with simple Illuminating Apparatus with iris diaphragm, and simpler Optical Outfit for 60—730 diameters 54.404. Medium Microscope, Stand IV, with rectangular fixed stage, coarse focussing by sliding tube, fine focussing by micrometer screw, millimetre graduation on draw tube. Abbe Illuminating Apparatus with iris diaphragm, Optical Outfit for 60 — 1000 diameters, together with box The Optical Outfit consists of 2 achromatic objectives, 1 homogeneous oil-immersion objective, and 2 Huyghenian oculars. 54.405. — idem, with simple Illuminating Apparatus, and simpler Optical Outfit, for 60 — 730 diameters 54.406. - - idem, without Illuminating Apparatus, with concave and plane mirror, with Optical Outfit for 70 — 575 diameters 54.407. Laboratory Microscope, Stand V, Figure, focussing by fine rack and pinion motion, largo, stage, draw tube, concave and plane mirror, with 2 achromatic objectives and 2 Huyghenian oculars, for 20 — 280 diameters 54.408. - - i d o m, simpler, tube without extension, with triple objective, 2 Huyghenian oculars, and box 54.409. Crystallisation Microscope after Lehmann, for observing the physical behaviour of preparations, specially of liquid and apparently live crystals, of. Fig. 54,409, with heating and cooling device, for observations in direct ami polarised light, with simple Optical Outfit with micrometer ocular and 2 objectives, with arrangement for testing the axial emissions in converging light The Stand has two stages rotary about the optical axis. The lower one is concealed and has £ s. d. 13. 10. 0 10. 0.0 12. 0.0 9. 0.0 5.15.0 4. 10. 0 3. 30. (I. 0 C'l. 5938, 5934 a, 4»39. No. 51423. Microscopes and Auxiliary Apparatus. 537 54 415. 1 : 3. a graduation of 360°; it can easily be rotated and rapidly returned to the zero position. Two blow- £ s. d. tubes can be fixed to the stage for cooling the preparations, a rapid and fine temperature regulation being rendered possible by this means. Three mirrors are used as polarisers; the illuminating mirror is arranged to rotate so that rapid change is possible from direct to parallel, polarised illumination. The burner has a regulating air and gas lead. The tube possesses a rack and pinion coarse focussing and micrometer screw fine focussing. Supplied with the instrument are two burners, two blow-pipes, one blue glass, three plano- convex lenses as cover glasses (for determining the refractive index), one heater, one double bellows, and one mahogany case for storing the instrument. Projection Microscopes as suggested by Lehmann: see No.«. 51,057 — 51,061, p. 183. 54,410. Mineralogical Stand, with tongs objective changer having three inset rings, achromatic objectives Nos. 1, 3 and 6, oculars I and III, micrometer ocular II, also gypsum and mica plates l/t wave-length The coarse focussing is secured by rack and pinion, and the fine by micrometer screw. The tube has a graduation and a centering head with locking gap for taking gypsum and mica compensators. The tube analyser can be switched in and out of the path of the rays. The condenser and polariser can be raised and lowered by a lateral screw. The change from converging to parallel light is done by a quarter-turn of a lateral knob and the polariser can be taken out of the condenser lens. The stage is graduated in 1/,° and permits of reading by vernier accurately to 1/10°- The surface of the stage has a position-finding graduation. 54.415. Large Preparation Stand, Figure, with heavy horse-shoe shape base, stage 100 xlOO mm with glass plate and hollowed metal trough; focussing by rack and pinion; cheeks for supporting the hands. With movable mirror, lens system comprising 3 aplanatic magnifiers, for magnifications of 8, 14 and 20 54.416. - - idem, with 2 aplanatic magnifiers for 8 and 14 diameters, and with a Preparation System consisting of 3 aplanatic lenses (as objective) and an achromatic ocular, for 15, 20 und 30 diameters when not using ocular, and 40, 60 and 100 with use of ocular. Auxiliary Apparatus for Microscopes. 54.417. Micrometer Ocular, with lateral slot for inserting the micrometer 54.418. Ocular Glass Micrometer, for inserting in the ocular, 5 mm = 100 divisions 54.419. --idem, 5 mm = 50 divisions 54.420. Object Micrometer, 1 mm = 100 divisions, glass graduation 54,421. Ocular Net Micrometer for counting objects strewn over the field of view, in mount, distance apart of lines 0.5 mm 54,422. Indicating Apparatus after Abbe 54,423. Microtome, simple pattern, for freehand cutting The specimen is clamped in a cylinder which can be screwed 10 mm below the surface of the table. One graduation of the micrometer screw is equivalent to raising the object 0.01 mm. The blade of the knife is guided over the glass table, the diameter of which is 70 mm. Cl. 5933. 19. 0.0 4. 0.0 5. 0.0 0.12.0 0. 4.0 0. 3.0 0. 6.0 0. 5.0 2. 2.0 0.18.0 538 Auxiliary Apparatus Jor Microscopes. Solar Microscopes. No. 54 424 - 54432. 2:3. 54427. 1:2. 54440. 1:4. 54.424. Microtome Knife, fitting Microtome No. 54,423 54.425. Slide-rest Microtome with automatic arrangement for raising the specimens 0.005 mm or multiples of this, without cutter . . The cutter slider is conducted to and fro after the manner of a lathe slide-rest thus rendering manipulation rapid and certain. The clamping device for the specimen is arranged movable on two intersecting axes. 54.426. Microtome Cutter after Jung, for preceding Microtome, 16 cm long Heating Boxes for embedding specimens in paraffin quoted for on application. 54.427. Hematometer after Thoma, Figure, with counting chamber and calibrating pipette for white and red blood corpuscles 54.428. Polarisation Apparatus for investigations on minerals and foodstuffs, analyser with divided circle If this apparatus is not ordered at the same time as the Microscope, the instrument must be sent to us. 54.429. Gypsum and Mica Plates, set of 8 54.430. Object Carrier with hollow ground out 16 mm diameter . Per 10 54.431. Object Carrier, 76x26 mm, with ground edges Per 100 54,432. Cover Glass Calipers, Figure The graduation gives hundredths of a millimetre direct. Range, over 5 mm. Cover Glasses, square, 0.14 — 0.17 mm thick: List No. Length of Side mm Per Hundred £ - idem, round: List No. Diameter mm Per Hundred £ 54,433 15 0.1.6 54,434 18 0.2.0 54,435 20 0.2.6 54,435 a 24 0.3.6 54,436 54,437 54,438 54,439 15 18 20 24 0.1.6 0.2.3 0.2.9 0.3.6 51.062. Collection of Microscopical Preparations for School Use, 50 specimens in small bag, with description: sec No. 51,062, p. 184 51.063. -- idem, 50 specimens (different collection): see p. 184 Glass Rods, Platinum Spatulse and small Scoops, etc. quoted for on application. Materials for Microscopy, as Canada Balsam, Lacquer, etc., of the best quality. 54.440. Set of Accessories for Microscopy, F i g u r c, case containing a razor, spatula. '2 small knives, straight and bent scissors, forceps, 2 preparation needles. 2 lancets 54.441. — idem, case with razor, spatula, small knife. 2 preparation needles, scissors, forceps 54.442. - - idem, case with small knife, scissors, forceps, 2 needles £ s. (1. 0. 4.0 6. 0.0 0. 18. 0 1.10.0 3. 0.0 0. 18. 0 0. 2.0 0. 3.0 1. 10. (i 1. 15. 0 1.18.0 (I. 15.0 II. 12. 0 0. 7.0 Microscopy Lamps: sec pp. 20 and 71. I'l. 1555. 4842. 1558. No. 54 449. Auxiliary Apparatus for Microscopes. Solar Microscopes. 539 54443. 1:5. 50 212. 1 : 7. 54 444. 1 : 4. £ s. d. 1. 0.0 6. 0.0 54.443. 6 Small Coloured Bottles in Stand with Droppers which serve as stoppers, Figure, for making coloured microscopical specimens 54.444. Micro-photographic Apparatus, Figure, with 2 dark slides, 1 ground glass and 1 transparent plate, 1 ground glass plate on stand, yellow, green and blue glass discs: price without microscope stand Two metal columns sliding in each other are mounted on an iron base, the camera resting on these columns. Any microscope stand can be used with the apparatus. By sliding the camera it is possible to compensate for the in equality in height of the different stands. The diaphragms whict can be slipped into the neck of the camera fix the limits of the image on the plate. A magnifier placed above the camera permits of fine focussing. The slides are suitable for plates 9 x 12 and 13 x 18 cm. 54.445. Focussing Stage or above 0. 15. 0 54 446. Auer Lamp with Reflector 0. 18. 0 54,447. Illuminating Lens 100 mm diameter, on stand 1. 4. 0 Solar Microscopes. 54,448. Solar Microscope, Figure, constructed entirely of brass, arranged for fitting on one of the hcliostats Xos. 50,205 — 50,212, with alum trough for absorbing the heat rays; the objective and illuminating lenses are focussed by two racks having sloping teeth, thus seQiiring quite uniform motion. For objective see Nos. 54,453 — 54,455 . 6. 0.0 54,449. Solar Microscope combined with Heliostat No. 50,212, Figure. Solar Microscope as before, Heliostat for screwing to the shutter; with horizontal toothed-wheel motion; mirror actuated by endless screw; with one attachment having a straight gap and one at- tachment with rotary disc which contains a wavy gap and holes of different size . . 12. 0. 0 Tables for Microscope work: see Nos. 50,362— 50,367, pp. 69 and 70. C'l. 3804, 1565. 156B, 1560. 540 Solar Microscopes. No. 54450 — 54 457. 1 : 2. 54461 — 54463. 1:4 — 1:8. 54 460. 1:3 — 1:4. 54,450. Solar Microscope combined with Wall Heliostat No. 50,208, for wall thickness to 54 cm 54.451. - - idem, with Wall Heliostat No. 50,209, for wall thickness of 60 cm 54.452. — idem, with Wall Heliostat No. 50,210 for 78 cm wall thickness . £ s. d. 12. 10. 0 13. 5.0 14. 0.0 Objectives for preceding Solar Microscopes: List No. 54,453 54,454 54,455 Size 1 2 3a £ 0.18.0 0.18.0 1.4.0 51.054. Revolving Nose-piece for 2 Objectives, for rapidly changing the magnification . . . 51.055. Revolving Nose-piece for 3 Objectives . . 54,456. Microscopical Specimens Each 7 d., 10 d., 1 s. 0 d. and Complete price list on application. See also Nos. 51,062 — 51,063. Hand Telescopes. Goerz "Trieder" Binoculars, Figure: List No. 54,457 54,458 54,459 Power 6 8 1:.' Weight 360 515 590 grams £ 6. 10. 0 7. 0. 0 9. 10. 0 54,460. Field and Opera Glasses, Figure, with 6 and 12 lenses. Prices according to style and quality .... £ 0. 15. 0, 0. 18. 0, 1. 0. 0, 1. 4. 0, 1. 7. 0, 1. 10. 0, 1. 13. 0 to Telescopes with extensions, with strap; Figure: List No. 54,461 54,462 54,463 Diam. of Objective mm 29 .'?(> (."> £ 1.0.0 1.5.0 2.0.0 0. 16. 0 1. 2.0 0. 1.6 5. 0. 0 Cl. 1524, 1523. 1525. 1567. No. 54473. Solar Microscopes. Opera, etc. Glasses. Telescopes. 541 54472, 54472a. 1: 16. 54473, 54 473 a, 54 473 b. 1:11. Astronomical Telescopes. Telescopes, Fig. 54,470, on metal stands having horizontal and vertical hand motion, in lock-up box: Diameter of Number of Oculars Powers ' Without a) Extra b) Extra . Objective i O terrest- astro- terrest- astro- Finder Price for Finder Price for Fine Motion mm rial nomical rial nomical £ s. d. £ s. d. £ s. d. 54464 36 1 — 22 — 4. 0.0 2.5.0 6. 0.0 54465 41 1 24 — 5. 0.0 2.5.0 6. 0.0 54466 48 1 — 28 — 6. 10. 0 2.5.0 6. 0.0 54 467 59 1 1 34 48 10. 0.0 2.5.0 6. 0.0 54468 68 1 2 42 60, 90 12. 10. 0 2.5.0 6. 0.0 54469 75 1 3 50 48, 72, 108 16. 10. 0 2.5.0 6. 0.0 54470 82 1 3 50 56,84,126 21. 0.0 2.5.0 6. 0.0 £ s. d. The fine motion listed under (b) permits of pointing in a horizontal and vertical direction, cf. Pig. 54,473. Telescopes with simple Wood Stand, for setting up on the floor, Fig. 54,472, tube in case. Diameter of Objective No. mm Number of Oculars terrest- astro- rial nomical PC terrest- rial wers astro- nomical Without Finder £ ». d. a) Extra Price for Finder £ s. d. b) Extra Price for Fine Motion £ s. d. 54 471 68 54 472 75 54 473 82 1 2 1 3 1 3 42 50 50 60, 90 48,72,108 56,84,150 12.10.0 15. 0.0 19. 10. 0 2.5.0 2.5.0 2.5.0 5. 0.0 5. 0.0 5. 0.0 The fine motion listed under (b) permits of setting in a horizontal and vertical direction, cf. Fig. 54,473. Cl. 1569. 6010. 542 Telescopes. Interference and Diffraction. No. 54 474 — 54 474 a. 1:13. 54488. 1:14. Telescopes with heavy Wood Tripod Stands, Fig. 54,474, for setting up on the floor, up-and- down motion by crank, horizontal and vertical hand motion for telescope; with Finder: £ s. d. List No. Diam. of Objective mm Number ( terrest- rial >f Oculars astro- nomical terrest- rial Powers astronomical a) With Finder £ s. d. b) K \tra Price for Fine Motion £ s. d. 54474 54475 54476 54477 54478 54479 54480 82 95 109 122 135 148 162 1 2 2 1 1 1 1 3 4 4 5 5 6 6 50 60, 90 66, 100 66 72 52 56 56, 84, 126 48, 72, 108, 162 54, 80, 120, 180 88, 132, 198, 264, 330 96, 144, 216, 288, 360 78, 104, 156, 234, 312, 390 84, 112, 168, 252, 336, 420 27.10.0 34. 0.0 47.10.0 62.10.0 70. 0.0 87. 10. 0 105. 0. 0 7.0.0 7.0.0 7. 0.0 7. 0.0 7. 0.0 7. 0.0 7. 0.0 The fine motion listed under (b) renders it possible to set the instrument in a horizontal ami vertical direction, cf. Fig. 54,473. 54,481. Parallactically Mounted School Telescope after Archenhohl, with achromatic objective 54 mm aperture, ocular focussing with rack and pinion, objective cap with aperture (which can be closed) for solar observations, a power 36 terrestrial ocular and a 48 power CI. 3406, 6004. No. 54 501. Telescopes. Interference of Thin Sheets. 543 54500. 1:1 54501. 1:3. astronomical ocular, with smoked glass, stand for erecting at the height of the table, and box If desired, instead of supplying the terrestrial eyepiece, 2 astronomical eyepieces (power 24 and 96 respectively) are provided with the instrument. The axial system is arranged for a mean polar height of 50°, but the polar height can be varied between 48° and 53°. 54.482. Graduated Circle for right ascension and declination, reading to 1° Extra 54.483. Ocular Prism for observing objects in the neighbourhood of zenith 54.484. Astronomical Eyepiece for powers 32, 72, or 120 Each Telescopes, mounted parallactically and balanced, with metal stand, F i g. 54,488, for setting up at table height, with lock-up box. for the tube. List No. Diameter of Objective mm Number < terrest- rial if Oculars astro- nomical terrest- rial Powers astronomical With compound Fine Motion, without Finder £ s. d. a) Extra Price for Finder £ s. d. 54485 54486 54487 54488 54489 48 59 68 75 82 1 1 1 1 1 1 2 3 3 28 34 42 50 50 48 60, 90 48, 72, 108 56, 84, 126 20. 0.0 22. 10. 0 25. 0.0 27. 10. 0 30. 0.0 2.5.0 2.5.0 2.5.0 2.5.0 2.5.0 Telescopes with Zeiss Optical Outfits, on wood stand, with rack and pinion height-motion, tube and accessories in box, stand-head in sail-cloth bag. Diameter of Number of Oculars Powers Without List No Objective terrest- astro- terrest- astronomical Finder mm rial nomical rial £ s. d. 54 490 70 1 4 47 41, 57, 82, 114 37.10.0 54 491 80 1 4 44 48, 67, 97, 134 42. 10. 0 54 492 90 1 4 50 54, 75, 108, 150 52. 10. 0 Useful Auxiliaries: 54.493. Fine Motion in azimuth and altitude 51.494. Power 8 Finder 54.495. Change Device 54.496. Zenith Prism 54.497. Herschel Solar Prism 54.498. Ocular Spectroscope 54.499. Ring Micrometer £ s. d. 9. 0.0 1. 10. 0 0. 15. 0 0. 15. 0 10. 0. 0 5. 0. 0 1. 12. 0 3. 10. 0 5. 5. 0 1. 16. 0 1. 12. 0 1. 0.0 54,500. Dynameter after Eamsden, Figure, for direct determination of the power of a telescope (M. P., 9th Edn., II, 1, p. 872) Interference and Diffraction. 52,045. Glass Balloon with Glycerine-soap Solution, after Eisenlohr, for showing Newton's Eings in thin liquid films, Fig. 52,045, p. 284, for the Whirling Table 154,501. Small Metal Frame for Soap Solution, Figure, for demonstrating the colours- of j thin plates (Graetz, ,,Das Licht und die Farben", Fig. 65; W. D. p. 445) j 0. 2. 0 0. 7.0 * Can be used with the Projection Apparatus. Cl. 1576, 824. 544 Interference and Diffraction. No. 54 502 — 54 504. 1 : 2. 54 514. 1 : 3. 54509 — 54512. 1:7. 54 517 A. 1:2. 54 517 B. 1:2. 54.502. 2 Glass Discs clamped together, with layer between, for demonstrating interference in wedge-shape air plates (M. T. p. 211; M. P. 10th Edn., II, 1, Fig. 608) 54.503. 2 Gold Leaves between Glass Plates, one appearing green and one blue when light is transmitted 54.504. Comparison of Superficial Colours, after Hartl, Figure; in reflected and incident light the colours of the four different thin plates appear in the complementary colours (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 133) * Newton's Colour Glasses, in brass mounts, with 6 pressure screws, for observing the inter- ference rings in a subjective and objective manner: List No. 54,505 54,506 54,507 54,508 Diameter mm 70 100 120 150 £ 0.16.0 1.0.0 1.4.0 1.12.0 * -- idem, rotary on stand, Figure. List No. 54,509 54,510 54,511 54,512 Diameter mm 70 100 120 150 £ 1.12.0 1.18.0 2.4.0 2.10.0 54,513. Colour Ring Apparatus for Students' Exercises, after Grimsehl, for determining wa\e- lengths by the aid of Newton's Colour Kings: comprising a reflector, a spectacle lens, a small auxiliary apparatus and an attachment for producing monochromatic light for Bunsen burners (E. Grimsehl, Ausgewahlte Schuleriibungen, Fig. 11) * 54,514. Interference Apparatus for Fresnel's Mirror Experiment, Figure, for screwing into the objective holder of the Projection Apparatus, in place of the objective, with adjustable gap, adjustable black mirrors and diaphragm; for Projection Apparatuses having 43 mm cliam. objective This apparatus considerably facilitates the carrying out of Fresnel's Experiment, since the gap and mirrors are combined ready for use. * 54,515. --idem, for Projection Apparatuses having 55 mm diam. objective * 54,516. — idem, for Projection Apparatuses having 60 mm diam. objective . . . £ s. d. 0. 4.0 0. 3.0 0. 8.0 0.14. (> 4. o. 4. <>. it * Can be used with th? Projection Apparatus. Cl. 4938, 5791, 353. 1577, 1578. No. 54531. Interference Mirrors. Adjustable Gaps. 545 54 523. 1 : 4. 54525 (54540). 1 : 4. 54 530. 1 : 7. 54 531. 1 : 6. * Fresnel's Mirror Apparatus, Figs. 54,517 A and B, with two black ground mirrors; one mirror £ s. d. centered by three screws, the other adjustable relatively to the others by fine screw, on Stand: List No. 54,517 54,518 54,519 Size of Mirrors mm 30x40 40x50 50x60 £ 2.2.0 2.8.0 3.0.0 Fig. 54,517 A shows the front, and Fig. 54,5178 the back of the interference mirror. * -- idem, simple, with cemented, ground mirrors: List No. 54,520 54,521 54,522 Size of Mirrors mm 30x40 40x50 50x60 £ 1.4.0 1.12.0 2.0.0 * 54,523. Interference Mirror after Fresnel, Figure, with parallel micrometer motion, micro- meter screw with drum and graduation, on stand, most carefully constructed .... 7. 0.0 * 54,524. - - idem, without micrometer motion 4. 16. 0 * 54,525. Ocular Micrometer after Fresnel, Figure, for measuring interference bands, on stand 6. 0.0 54,526. Fresnel's Mirror for Students' Use, after Grimsehl, for determining the wave length of light, with gap, micrometer graduation and two mounts (E. Grimsehl, Ausgewahlte Schuleriibungen, Figs. 2 and 3) 0.14.0 Lenses: see No. 53,932 b. Adjustable Gaps: see Nos. 54,530—54,535. * 54,527. Interference Apparatus after Grimsehl, constructed on the Lloyd single mirror prin- ciple, thus doing away with adjustment of the mirrors. The direct and the reflected image of the gap are used together for interference (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 217). The gap with micrometer screw for adjusting and screw for narrowing and widening are on stand 3. 10. 0 54.528. Screen with ground glass disc and millimetre graduation for determining wave length; for use with red and blue glass discs, and especially with the preceding Grimsehl Inter- ference Apparatus (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 218) 1. 10. 0 54.529. Interference Apparatus after Classen, for demonstrating the phenomena before a large audience ; interference is produced by reflection on two glass plates (Hassack-Rosen- berg, Projektionsapparate, p. 230; Classen, Natur des Lichts, Fig. 9) 2.10.0 54.530. Adjustable Gap, Figure, with diaphragm screen, on stand, cf. No. 50,985 ... 1. 3. 0 54.531. -- idem, with Micrometer Screw, Figure, on Stand, cf. No. 50,986 1.13.0 * Can be used with the Projec- Small transparent Projection Screen: tion Apparatus. see No. 51,003, p. 179. ii02.326.32o. 35 546 Interference and Diffraction. No. 54 532 — 54 539. 1 : 2. 54 532. 1 : 9. 54536. 1:10. 54 537. 1 : 4. 54 540 A. 1:9. 54.532. Adjustable Gap, can be used vertically and horizontally, Figure, on Stand . . 54.533. - - idem, with Micrometer Screw . 54.534. Adjustable Gap with iris diaphragm, cf. Fig. 50,988, p. 176, on stand; the length of the gap can also be altered by the iris diaphragm 54.535. - - idem, with Micrometer Screw Adjustable Gaps for the Projection Lantern: sec under Nos. 50,985 — 50,988 a, pp. 175 and 176. 54.536. Interference Prism (bi-prism) after Fresnel, Figure, with diaphragm (M. P., 10th Edn. II, 1, Fig. 604), 30x40 mm, on Stand 54.537. Billet's Half-lenses, Figure, plano-convex, adjustable by micrometer screw, on stand, 60 mm diameter (M. P. II, 1, Fig. 605 [587]) 54.538. Lens of short focal length, for observing the interference bands, on Stand .... 54.539. Analyser after Dele/cnne, Figure, with two small parallel mirrors, for the inter- ference bands, in brass mount with haft M. 3408, 1581, 326", 308. £ s. d. 1. 6.0 1. Iti. 0 L>. 11.0 3. 1.0 1. 8.0 2.10.0 0.16.0 1. *.<> 1583, No. 54 541. Interference Bands, Diffraction Phenomena. 547 54 540 B (54668). 1 : 6. 54541. 1:8. * 54,540. Large Optical Bench for Interference and Diffraction Experiments, Figs. 54,540 A — J and 54,525, with auxiliary apparatus and box for same; for use with the Heliostat or Projection Lantern The bench is of iron, 1.20 m long, and is provided with levelling screws. It has a graduation in millimetres. Each of the three sliders has an index, one of these indices having cross motion for accurate adjustment. The screens fitted for taking the various gaps, gratings, apertures, lenses, etc. can be adjusted vertically on the pillars, in addition to being adjustable laterally. The following pertain to the bench: 1 cylindrical lens, 1 interference prism, 1 Fresnel ocular micrometer (Fig. 54,525) for measuring wave length, with red observation glass; 1 double adjustable rotary micrometer gap, Fig. C; 1 rotary gap with screw adjustment, 1 rotary double grating on glass, 3 screens for taking 12 diaphragms having apertures of different shape and with gratings and gaps of different width. The set of dia- phragms consists of: 1 diaphragm with sharp edge, Fig. D; 1 diaphragm with thick needle. Fig. E; 1 slot diaphragm with a hair, Fig. F; 1 diaphragm with a thick opaque fibre, Fig. G; 1 diaphragm with a small round aperture for Grimaldi's experiment, Fig. H; 1 diaphragm with large round aperture; 1 diaphragm with aperture half covered over with mica, Fig. J; 1 diaphragm with rhombic aperture. 1 diaphragm with triangle of holes, 1 diaphragm with two holes, 1 diaphragm with network of holes, and 1 diaphragm with a row of holes. * 54,541 . Diaphragmic Disc with 9 Schwerd apertures for diffraction phenomena, Figure, rotary, on Stand, for use with sunlight or electric light * Can be used with the Projection Apparatus. Cl. 309, 327, 310 £ s. d. 27.0.0 1.10.0 35* 548 Interference and Diffraction. No. 54 544 — 54 544 A. 1:6. 54 544 B. 1:4. 54 547. 1 : 10. 53,907. Cylindrical Lens, in mount, on Stand, 60 mm diameter, for observing the Fresnel diffraction bands (M. P. II, 1, p. 793 [944]) 53,908. --idem, 80 mm diameter 54.544. Diffraction Apparatus, Figs. A and B, consisting of an achromatic telescope of 30 mm aperture, on Stand • The following pertain to above: 1 gap attachment with micrometer screw, 2 attachments with rotary diaphragm discs having the following apertures: 1 round hole, 2 round holes, 3 round holes, 4 round holes, 1 triangle, 1 rectangle, 1 rhomb, 1 row of holes, 1 sieve, 1 double gap, 1 triple gap, 1 wire grating, 1 grating on glass (1 cm in 100 parts), 2 rhombs. The sets of gaps and diaphragms are contained in a case, Pig. B. 54.545. - - idem, with larger telescope having aperture of 40 mm, gap with micrometer screw and divided drum, fitted with finer glass grating and a larger number of diaphragms In addition to the diaphragms listed in previous item, this apparatus contains: 1 rotary dia- phragm disc with: 1 hole 0.4 mm diameter, 1 crossed wire grating, 1 needle, 1 hair, 1 small rod, 1 sharp edge, 1 small rod half covered with mica for showing the distortion of the interference bands. 54.546. Nickelled Metal Sphere, on stand, for producing a luminous point by reflection of sunlight 54.547. Diffraction Apparatus for determing the wave length of light, after Hoffmann, Figure (Ztschr. f. d. phys. u. chem. U. 14, 1901, p. 32), with three coloured discs The apparatus consists of an optical bench fixed on a stand and rotating about a horizontal axis, on which are placed a grating with observation tube and a diaphragm having a screen. These apparatus are capable of movement along the bench. The diaphragm consists of 3 parallel 0.5 mm wide gaps of different length placed at distances apart of 10 mm. Covers with coloured discs can be placed on the diaphragm. Three of these coloured discs (red, green and blue) are supplied with each apparatus. 54.548. - - idem, after Grimsehl (Ztschr. f. d. phys. u. chem. U. 17, 1904, p. 135) . . . 54.549. - - idem, for Students' Use, after Grimsehl, comprising Xernst Lamp on stand, diaphragm with aperture, 4 coloured glasses, small optical bench, glass micrometer (E. Grimsehl, Ausgewahlte physikalische Schuleriibungen, Figs. 8 — 10) Glass Gratings: List No. 54,550 54,551 54,552 54,553 54,554 54,555 Lines to 1 cm 50 100 200 300 500 1000 £ 0.5.0 0.7.0 0.14.0 1.2.0 1.16.0 2.16.0 54,556 54,557 2000 3(lO<) 3. 10. 0 4. 0. 0 54,558. Double Grating, in Brass Mount, rotary one above the other, Figure, 1 mm in 7.10.0 11. 0.0 0.16.0 6. 0.0 2. 10. 0 2. 15.0 0. 18.0 13 parts 54,559. Wire Grating i 0. 10.0 Cl. 1585, 1586, 1584 No. 54 576. Diffraction Apparatus. Diffraction Gratings. 549 54 558. 2 : 3. i 54 568. 1 : 3. MAX KOHL. CHEMNITZ 54 561. 1 : 2. 54 566, 54 568. 1 : 2. 54 576. 1 : 54.560. Photographed Grating after Xobert, 3 cm wide with lines 3 cm long; 1000 lines to 1 cm , On account of its brightness this grating is well adapted for demonstration purposes, but not for accurate measurements. 54.561. Copy of a genuine Rowland Grating, Figure, 50 x35 mm area of grating, in case 54.562. - - idem, smaller, 25 X 20 mm area of grating 54.563. - - idem, between two glass prisms inclined 7° and 32 mm square, Figure . 54.564. Photographed Diffraction Grating, cemented as a lantern slide between glass plates, 115 lines to the millimetre, area 63 square millimetres 54,565. - - idem, photographed area 25 x 25 mm 54,566. Diffraction Grating after Henry A. Eowland, with 14,438 rulings to one inch, Figure, plane or concave, of the highest perfection As a rule we keep a number of such gratings in stock; kindly state requirements. Stands for Rowland's Diffraction Gratings, Figs. 54,568, accurately constructed: List No. 54,567 54,568 54,569 54,570 54,570 a Suitable for Gratings of 1.4" 2.5" 4" 5" 6" £ 2.10.0 3.10.0 4.0.0 4.10.0 5.0.0 Fig. 54,566 shows the stand with the grating set up on it. - idem, simple pattern : List No. 54,571 54,572 54,573 54,574 54,574 a Suitable for Gratings of 1.4" 2.5" 4" 5" 6" £ 0. 12. 0 0. 18. 0 1. 4. 0 1. 10. 0 1. 16. 0 * 54,575. Phase Reversing Plate, after E. W. Wood, consisting of a glass plate covered with a, large number of concentric rings of different fineness and acting as a lens, 180 cm focal length (Phil. Mag. 1898, p. 511) The plate of 180 cm focal length gives an image of the arc at a distance of approximately 2.5 m from an arc light regulator at a distance of approx. 4 m. The plate of 40 cm focal length can be used as landscape objective with the aid of a weak convex lens. * 54,576. Circular Photographed Grating, Figure, graduated area 76 mm diameter, about 200 lines to the millimetre If an image of tlie arc of an electric projection lamp is cast on the screen and if the circular grating is placed on it centrally in front of the objective, an annular rainbow results. € s. d. 0.18.0 1. 4.0 0.15.0 2. 0.0 0.10.0 0. 5.0 Price on appli- cation # Can be used with the Projection Apparatus. Cl. 1588, 3685, 1591, 1589, 0.10.0 1. 0.0 1590, 3686. 550 Interference and Diffraction. No 54 577 - 54 585. 1 : 2. 54 577. 1 : 8. 54 588. 1 : 6. 54,577. Diffraction Chromoscope after Ives, cf. Figure, with binocular objective and with 6 image plates, size of image approx. 6.5 cm The photo plates are made by Wood's process; they consist of three superposed photographed grating plates each of which has small grating surfaces corresponding to the individual shapes of the image. The gratings of the three plates have graduation of different widths thus producing spectra of different lengths. If lateral illumination is applied to an image plate in the apparatus, the portions of the image plate, which contain only one portion of the grating, cast a definite colour of the spectrum towards the point at which the eye is situated; immediately two or three gratings act simultaneously on the eye, the eye itself perceives a corresponding mixed light. At the places on which the image plate contains no grating the light is not diffracted and no luminous rays pass through the plate to the eye, since the source of light is situated laterally to the photo plate; consequently these portions appear black. The image plates can also be used for objective demonstration (cf. B. Donath: Ad- ditive Farbenwiedergabe nach Wood mit Hilfe von Beugungsspektren, Brunswick, 1906, pp. 125 et seq.). Diffraction Chromoscopes for Projection: see Nos. 51,066 and 51,066 a, p. 185. Interference Plate after Lumner-Gehrcke : see No. 54,089, p. 507. Echelon Grating after Michelson: see No. 54,090, p. 507. Interference Air Plate after Fabry and Perot: see No. 54,091, p. 507. 54.579. Photographs of the Solar Spectrum, after H. A. Eowland . . . Sulliman's Journal of Science, 1887/8. Complete series of 10 plates, size 90 x 30 cm, drawn on lines, provided with the normal wave length scale as corrected by Rowland. The series contains all wave lengths from 300 to 695 fifi. 54.580. - - A single plate 54.581. Extra Plate of the B lines in same size 54.582. Extra Plate of the D lines, same size The B lines have an expansion of 600 mm, the D lines a distance of 75 mm. 54.583. 4 Extra Plates with the carbon lines Each £ 0. 18. 0 * 54,584. Dust Glass for colour rings, very pretty experiment by means of the Projection Lantern . . . , The objective head should be removed from the lantern and a diaphragm having a small round aperture placed in front of the condenser; a bi-convex lens of approx. 50 cm focal distance should now be placed in the luminous pencil so as to render the rays convergent. The dust glass is held immediately behind the lens. * 54,585. Reflecting Stephanoscope after von Lommel, small pattern, for demonstrating inter- ference of diffracted light, Figure (Fr. phys. Techn. II, 2, Fig. 2877 [II, Fig. 844]) * 54,586. - - idem, larger, for objective demonstration Polarisation of Light. 54.587. Polariser and Analyser after Mace* de Le"pinay, for explaining the polarisation of light on a vibrating fibre which is actuated by an electrom&gnetically driven tuning fork, 1.5 m long (Ztschr. f. d. phys. u. ohem. TJ. 2, 1888, p. 87; W. D., p. 454 [416]) . . 54.588. Model for Explaining Polarisation by Reflection and Refraction, Figure .... The different directions in which the ether particles vibrate are demonstrated by small cross rods. £ s. d. 5. 0.0 7.10.0 0.18.0 0.18.0 0.18.0 3.12.0 0. 4.0 0.16.0 1. 6.0 11. 0.0 0.18.0 * Can be used with the Projection Apparatus. Cl. 3675, 3805, 1598. No. 54594. Polarisation of Light. 551 54 593. 1 : 12. 54 594. 1 : 5. Apparatus for Fresnel's Explanation of the Rotation of the Plane of Polarisation; see Nos. 51,817 and 51,818, p. 259. 54,589. Model for showing the Rotation of the Plane of Polarisation in quartz and in a sugar solution, after Grimsehl (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 220) * 52,047. Polarisation Apparatus for Demonstrating the Properties of Polarised Light, for the Whirling Table (M. P. II, 1, Fig. 693 [671]), see Fig. 52,047, p. 285 * 54,590. Polarisation Apparatus for the Projection Lantern, Figure (W. D., Fig. 322 [304]) The apparatus consists of a screen with tube, an uncoated mirror as polariser, a black mirror and a set of glass plates each with tube and rotary mount, as analysers. * ~>4,o!)l. Further Set of Glass Plates for No. 54,590, for use as polariser (W. D. p. 451 [414]) * 54,592. Polarisation Apparatus after Duboscq, Figure, for the Projection Lantern (M. P., 9th Edn., II, 1, Fig. 638), with two mirrors, lens and receiving screen, on stands . . * 54,593. Polarisation Apparatus, Figure, for objective demonstration of the phenomena of polarisation by reflection and refraction (M. P. II, 1, Fig. 699 [677]), with 2 glass plate columns, diaphragm and lens, on tall stands; can be used with the heliostat or a projection lantern * 54,594. Demonstration Polariser after Grimsehl, Figure (Ztschr. f. d. phys. u. chem. U. 18, 1905, p. 321), with direct vision for demonstrations In this very neatly constructed apparatus a coated mirror and a blask mirror a.e filled as reflection polariser. The apparatus can be rotated about the axis formed by the incident ray of light. The angle at which the ray of light falls on the polariser is 55°. A convex lens given in is used for experiments with converging polarised light. No. 54,595 is used as analyser. £ s. d. 3. 0.0 1.10.0 2. 8.0 0. 18. 0 3.12.0 4.15.0 1. 2.0 * Can be used with the Projection Apparatus. Cl. 313, 314, 31fil, 3152, 3806. 552 Polarisation of Light. No. 54595 — 54597. 1 : 10. 54 595 A. 1:10. 54 595 B. 1:10. 51 074. 1 : 4. 54 600. 1 : 6. * 54,595. Demonstration Analyser for polarised light, after Grimsehl, Figs. A and B (Ztschr. f. d. phys. u. chem. U. 18, 1905, p. 322), consisting of a screen on stand with one four-sided pyramid of black glass plate and one black glass sphere on haft .... Fig. A shows a reflected image of the pyramid produced on the analyser screen by the polariser No. 54,594; Fig. B showing a reflected image of the glass sphere. When the polariser is rotated the images rotate along with it. * 54,596. Plate of Mirror Glass with Haft, for insertion as an analyser in the screen of No. 54,595 (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 219) #54,597. Glass Tube for Polarisation Experiments with Liquids, aftor Grimsehl, Figure (Ztschr. f. d. phys. u. chem. U. 18, 1905, p. 324), with two stands, closed on one side by a plane glass disc, with stopper; for use with polariser No. 54,594 The liquids to be tested — water or sugar solution — are rendered cloudy by the addition of a considerably diluted alcoholic mastic solution. The illuminated straight zone of the water and the spirally twisted zone of the sugar solution respectively rotate when the polariser is rotated. * 54,598. Auxiliary Apparatus after Grimsehl, for objectively demonstrating the Calc-spar cross (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 219, Fig. 11), with reflex polariser . . * 54,599. Demonstration Polarisation Apparatus, direct vision, after Grimsehl, arranged for inserting preparations (Xtsclir. f. d. phys. u. chem. U. 18, 1905, p. 325, 326, Fig. 6) This apparatus consists of two movable polarisers No. .~>4.."i!l4 connected together, one of which acts as an analyser. It is possible to demonstrate objectively with them the ordinary phenomena of polarisation by using a projection lantern arid a transparent screen No. 51.003. £ s. d. 1.15.0 0. 6.0 1. 8.0 2. 0.0 1.10.0 * Can be used with the Projection Apparatus. a. 3807, 3809, . 3808,317. 3:«. No. 54 605. Polarisation Apparatus. 553 54 602. 1 : 4. 54 604. 1 : 6. * 54,600. Simple Polarisation Apparatus, Figure (Tyndall, Das Licht [Light], p. 125), with two large tourmaline plates 5x15 mm, fastened on the glass, one of which is rotary . . * 51,074. Polarisation Apparatus for Objective Demonstration, Figure (W. D., Fig. 323 [305]) * 54,601. 1 Set of Preparations for preceding apparatus: 2 gypsum figures, 2 rapidly annealed glasses, 2 gypsum plates, calc-spar, rock crystal, aragonite, potassium-cyanide, strontium copper acetate and tourmaline 54.602. Large Projection-Polarisation Apparatus after Duboscq and von Lang, Figure (M. P., 9th Edn., II, 1, Figs. 746 and 747), for use with the heliostat or projection lantern and for demonstrating all phenomena of double refraction and polarisation The apparatus consists of a rotary stand adjustable vertically containing one fixed and three sliding attachments; one condenser; 3 lenses; 4 calc-spar prisms as polariser; 1 Nicol as analyser and 1 bi-concave lens on stand for rendering the luminous rays of the projection lantern parallel. To the apparatus appertain: 1 Delezenne polariser; 1 black mirror; 1 gap; 1 set glass plates; 1 quartz plate cut parallel to the axis; 1 ditto cut perpendicular to the axis; 2 quarter-wave mica plates; 1 direct vision prism; 1 wedge compensator with quartz plate after Soleil and 1 double quartz plate; 2 gypsum plates: 1 piece aragonite; 1 piece tourmaline; 1 piece calc-spar; 1 gypsum figure. 54.603. Polarisation Apparatus after Norrenberg, simple, of brass, with coarsely divided circle, with rotary stage and with black mirror as analyser 54,603 a. -- idem, with Glass Plate Column as analyser 54.604. --idem, F i g u r e, with Nicol prism as analyser 54.605. - - id e m, with black mirror and glass plate column, without Nicol 54.606. - - i d e in, with black mirror, glass plate column and Nicol prism (Gan.-Atk., Figs. 654, 655; Gan.-Man., Figs. 439, 440) £ s. d. 3. 0.0 7. 0.0 3. 5.0 34. 0.0 2. 0.0 2. 5.0 2.10.0 2.10.0 3. 5.0 Can be used with Projection Apparatus. ci. 318, 1614. 554 Polarisation of Light. No. 54 607 — 54 607. 1 : 5. 54 609. 1 : 6. 54 610. 1 : 6. 54 612. 1 : 4. 54.607. Polarisation Apparatus after Norrenberg, Figure, entirely of brass, with finely divided circles, glass stage rotary and movable about the horizontal axis, with one lens, 1 black mirror, 1 column of glass plates (M. P. II, 1, Fig. 698 [676]) For simpler patterns, see preceding page. 54.608. - - idem, with 3 lenses, also with a Nicol prism as analyser 54.609. — idem, Figure, with 3 lenses, black mirror, column of glass plates, Nicol prism and tube for circular-polarising liquids 54.610. --idem, as No. 54,609, with a Vogel Pocket Spectroscope, for use as a Polarisation Spectroscope, Figure 54.611. Collection of Polarisation Preparations, suitable for Apparatus Nos. 54,602/9 and 54,618/20, consisting of 6 crystals and 2 rapidly annealed glasses •„ 54.612. Simple Polarisation Apparatus after Hartl, Figure, with wood stand, for taking preparations, and in particular the rapidly annealed glasses No. 53,863 (Fr. phys. Techn. II, 2, Fig. 2954) 54.613. Polarisation Apparatus for Students' Use, after Grimsehl (Grimsehl, Ausgewahlte physikalische Schtilerubungen, pp. 19 — 31) (a) Vertical and inclined glass plate with bases and Glow Lamp Holder on base for measuring the angle of polarisation on glass plates (£ 0.7.0); (b) Polarisation Apparatus with 2 inclined black glass plates, with preparation holder, for investigations between parallel polarisers (£ 0.4.0); (c) Po- larisation Apparatus with crossed polarisers, with preparation holder (£ 0.4.0); (d) Polarisation Appa- ratus arranged on Norrenberg's principle, with rotary set of glass plates (£ 1.10.0): (e) Preparations suitable for above: calc-spar, aragonite, gypsum plate 2 mm thick, gypsum plate 0.5 mm thick, gypsum image, butterfly (£ 1. 15. 0). For lenses, see No. 53, 932 b; for model for explaining polarisation in a thin gypsum sheet, see No. 54,686. * 54,614. Column of Glass Plates, Figure, formed of 15 — 20 thin plate glass sheets, in round mount with lateral opening so as to be capable of use in transmitted and reflect cd light, 65 mm diameter, 110 mm long Black Mirrors, in mahogany frame: List No. 54,615 10x20 0. 10. 0 Size cm £ 54,616 15x30 0. 18. 0 54,617 20x40 1. 10. 0 £ s. d. 4.16.0 6. 0.0 6.10.0 9. 0.0 1.16. d 0.10.0 4. 0.0 1.16.0 * Can be used with the Projection Apparatus. Cl. 1615, 1616,4814,5569. No. 54025. Polarisation Apparatus. Tourmaline Tongs. 555 54 621. 1 : 6. 54 622. 1 : 2. 54 624. 1 : 5. 54.618. Microscopic Polarisation Apparatus, Figure (M. P. II, 2, Fig. 802 [II, 1, 763]), with draw tube and lens system, for magnifying the axial images The apparatus possesses a very large field of view and permits of viewing simultaneously the poles of the rings in sodium hyposulphite. 54.619. --idem, Figure, with rack on draw tube and Goniometer for measuring the axial angles of the crystals 54.620. - - idem, with polished mahogany storing box With the last three apparatus listed it is possible to observe the axial images and other pheno- mena on crystal plates, gypsum and mica combinations, etc. 54.621. Large Polarisation Apparatus, Figure, with black mirror, Nicol prism, 3 lenses, preparation holder on one axis, with divided drum, provided with vernier and magnifier for reading off the rotation. The preparation holder can be rotated horizontally and vertically thus rendering possible the focussing of the axial images to a nicety. The apparatus has cross wires which can be adjusted symmetrically narrower and wider by a screw. The apparatus gives a very large and beautiful image 54.622. Tourmaline Tongs, Figure. Price according to beauty and purity of the tourma- lines (M. P. II, 1, Fig. 680 [654]) £ 0. 15. 0, 1. 0. 0, 1. 5. 0 .. 54.623. --idem, Figure, with device for automatically securing the preparations (M. P. II, 2, Fig. 799 [II, 1, 758]) 54.624. Tourmaline Tongs with 6 different preparations, Figure, with box ...... Preparations: sugar, amethyst, calc-spar (Iceland), smoky quartz, potassium-cyanide, aragonite. 54.625. Tourmaline Plates, green, singly Each £ 0. 6. 0 to s. d. 0.0 10. 0.0 11. 0.0 15. 0. 0 1.10.0 1.10.0 2.12.0 0. 10. 0 Cl. 321, 1617, 1618, 1621, 1619. 1620, 1622. 556 Polarisation of Light. Xo. 54 620 - 54 628. 1 : 3. 54 626. 1 : 4. 54 633. 2 : 5. 54 627. 1 = 2. * 54,626. Polarisation Apparatus after Mach, Figure, with rotary analyser (M. P. II, 2, Fig. 812 [II, 1, 749]), with 2 Nicol prisms, one of which rotates, with gap attachment, diaphragm attachment, glass press, object holder and direct-vision prism * 54,627. Wedge Compensator after Babinet, F i g u r (M. P. II, 2, Figs. 764, 765 [II, 1, Figs. 814, 815]), 2 wedges cut parallel to the axis, in mount * 54,628. Compensator after Soleil, 2 wedges and compensating plate, in brass mount, Figure (M. P., 10th Edn., II, 2, Fig. 766) 54.629. Polariscope after Savart, in brass mount 54.630. - - after Babinet 54.631. - - after Se"narmont 54.632. - - after Bravais 54.633. Fresnel's Parallelepiped, Figure, in brass mount (M. P. II, 2, Fig. 884 [II, 1, 827]) Paalzow Optical Benches. * 54,634. Large Paalzow Optical Bench, F i g u r e, for experiments on Double Eefraction, on Polarisation in parallel and converging light, on Interference and Diffraction, on Spec- trum Phenomena and on Microscopic Phenomena, by means of sunlight, electric light. or limelight; fitting all our projection apparatus The optical bench consists of an iron cheek I. -2 in long, pinned and ground, resting on legs having levelling screws. It is provided with a rule accurately divided in millimetres and has 7 brass stands. £ s. d. 13. 0.0 5. 0.0 6. 10. 0 0.18.0 1. 4.0 1.10.0 1.10.0 2. 8.0 34. 0.0 * Can be used with the Projection Apparatus. Cl. 320, 294, 1628, 293. No. 54 634. Paalzow Optical Benches. 557 54634. Large Paalzow Optical Bench, 1 : 7. Fitted with the undermentioned accessories and auxiliary apparatus No. 50,982, 50,986, 54,022, three of No. 54,180, Nos. 54,627, 54,637, 54,641, 54,644, 54,648, 54,650, 54,653, 54,664, 54,665 and 9 additional preparations. 6 of which can be adjusted vertically by rack and pinion; one of these can be adjusted laterally by a micrometer screw for carrying out interference experiments. The following experiments are possible when an appropriate selection of the accessories Nos. 54,636 to 54,669 is made. 1. Double refraction with one or two double refracting prisms, Fig. 54,635 d. 2. Breaking up of the unpolarised light into 2 or 4 polarised rays by double-refracting prism. 3. Polarisation by using a Nicol and a double-refracting prism, Fig. 54, 635 b. 4. Polarisation by a Nicol prism and a column of glass plates. 5. Polarisation by a Nicol prism and a black mirror. 6. Polarisation by a glass plate column and a black mirror, Fig. 54, 635 c. 7. Polarisation by 2 Nicol prisms in parallel light. 8. Polarisation by 2- Nicol prisms in strongly converging light, for monaxial and bi-axial crystals, Fig. 54,635 a. 9. Explanation of the scientific and technical polarisation apparatuses; Soleil's wedge compensation, colour apparatus and half-shadow apparatus by means of Lippich's polariser. 10. Demonstration of interference and diffraction phenomena. 11. Demonstration of spectrum phenomena by a gap, a collimator lens and a large direct-vision prism, Fig. 54,635e. 12. Demonstration of Microscopic phenomena in polarised light, Fig. 54,635 f. 13. Projection 01 microscopical preparations. As luminous source use can be made of a heliostat, of one of the projection apparatrs listed under Nos. 50,730 — 50,744, 50,783 — 50,806, or of the Megadiascopes Nos. 9500 — 9519. The most advantageous sources to use for these experiments are the apparatus having an electric arc lamp or, perhaps, limelight. The path of rays can be followed freely by the audience and the entire arrange- ment of lenses, objects, etc. is such that an image is first cast on the projection screen in unpolarised light, the objects then appearing in polarised light when the polarisers are inserted. Supplied with the apparatus are: 6 Stands, with up and down adjustment, five of these with rack and pinion. 1 Stand with lateral screw displacement for interference experiments. 1 Water Trough (£ 2. 0. 0) for continuous cooling, for condensers to 122 mm diameter (when using projection lanterns having larger condenser use should be made of larger troughs at an extra price of £ 0. 10. 0, see List No. 50,977). 1 Bi-concave Lens in mount (£ 1. 5. 0) for producing parallel rays (when ordering the size of condenser of the lantern should be given). 1 Rotary Object Holder (£ 1. 5. 0). 1 Open Objective (£ 1. 10. 0). 2 Bearings for the Nicol prisms (£ 0. 15. 0). 2 Condensers (£ 4. 0. 0) for producing strongly converging rays. One of these condensers is fitted with preparation holder. If desired, the accessories, together with any auxiliary parts ordered at the same time, are fitted in a durable box, at lowest possible price. Auxiliary parts for definite optical experiments: see Nos. 54,636 — 54,669. € s. d. 01. 2S9. 558 Polarisation of Light. No. 54 635 — N O K K N L TV - £1 '! 54641. 1:3. 54 635 a (50 789, 54 635, 54 639). 1 : 10. Polarisation in converging light with 2 Xicol prisms and 2 condensers, for uniaxial and bi-axial crystals. H W 54 635 b (54 635, 54 639, 54 649). 1 : 10. Polarisation in parallel light with 1 Nicol as polariser and 1 double-refracting prism. 54 635 c (54 635, 54 645, 54 647). 1 : 10. Polarisation with Column of Glass Plates and Black Mirror. The collections for different experiments are represented in Figs. 54,635 a — f; the projection apparatus, should be imagined as being to the right of the optical bench and the projection screen to the left. C = Collimator Lens, K = D = Direct -vision Prism, F = Adjustable Gap, L = 0 = Glass Plate Column. M = H = Rotary Object Holder, N = In the illustrations Condenser with Preparation O = Holder. P = Bi-concave Lens, Projection Microscope, S = Nicol Prism. W = Open Objective, Double - refract in. u Prism, Black Mirror, Water Trough. * 54,635. Small Paalzow Optical Bench, Figs, a — f, with tall legs, for experiments on Double i s. d. Infraction, Polarisation in parallel and converging Light, on Spectrum Phenomena and on Microscopical Phenomena 16. 0. O This optical bench consists of a polished stand of mahogany with two metal rails. Given in are the following: 7 simple stands sliding on the rails. 1 Water Trough (£ 2.0.0) for continuous cooling, for condensers to 122 mm diameter (when using projection lantern having larger condensers a larger trough, at an extra price of i 0. 10. 0, should projection lantern having larger em be employed, see List No. 50,977). * Can be used with the Projection Apparatus. 'l. 302, 291. 303. 304. No. 54647. Paalzow Optical Benches. 559 54 635 d (54 635, 54 649). 1:10. Double refraction with 1 or 2 double-refracting prisms. 54635e (54635, 54666, 50982, 50986). 1 : 10. Spectrum Phenomena with a direct-vision prism. N M N 54635! (54635, 54639, 51048, 54639). 1 : 10. Microscopic Polarisation Phenomena in converging light (can also be used as Projection Microscope). 54643. 1 : 3. 1 Bi-concave Lens in mount (£ 0. 18. 0) for producing parallel rays (when ordering size of condenser of lantern should be quoted). 1 Rotary Object Holder (£ 1. 5. 0). 1 Open Objective (£ 1. 10. 0). 2 Bearings for Nicol Prisms (£ 0. 10. 0). 2 Condensers (£ 4. 0. 0) for producing converging rays, with preparation holder. The preceding optical bench is specially adapted for experiments Nos. 1 — 9 and 11 — 13 included in the remark to List No. 54,634. If the bench has to be arranged for interference and diffraction experiments (see No. 10) also, it must be constructed longer, the extra cost being £ 2. 0. 0. £ s. d. Auxiliary Apparatus for Experiments on Polarisation and Double Refraction, Figs. 54635 a, i>. c, d. 54,636. Nicol Prisms in brass mount, polariscr 35 mm, ana- lyser 28 mm 50. f 54,637. — idem, polariser 30 mm, analyser 24 mm 30. The prices of the Nicol prisms are only approximate and liable to vary. 54,638. Divided Circle and Index on the prism mounts .... t 54,639. 2 Nicol Prisms in brass mount, polariser 25 mm, ana- lyser 22 mm, Fig. 54,635 b (N) and 54,635 f (N), quality I . .54,640. — idem, polariser 25 mm, analyser 20 mm, quality I . The prices of Nicol prisms are only approximate and sub- ject to variation. For large Paalzow Bench No. 54,634 £ S. d. 0. 0 0. 0 For small Paalzow Bench No. 54,635 £ s. d. Prices vary 1. 10. 0 — Prices 22-10' ° 1 20. 0. 0 The items marked f are absolutely necessary for carrying out the experiments. For large Paalzow Bench No. 54,634 £ s. d. 3. 0. 0 Cl. 305, 306, 307, 292. For small Paalzow Bench No. 54,635 £ s. d. 1. 2. 0 1. 2. 0 1 54,641. Glass Press, Figure, with 2 glasses, for showing that glass becomes double refracting by pressure (M. P. II, 2, Fig. 797 [II, 1, 790]) .... f 54,642. Fresnel's Press, for showing that pressure makes glass double refracting (M. P. II, 1, 753 [734]) 2. 15. 0 2. 15. 0 t 54,643. Glass Bending Press, F i- g u r e, with 2 glass strips, for producing double refraction (M. P. II, 2, 796 [II, 1, 789]) t 54,644. Black Mirror, with mount and haft t 54,645. - - idem, smaller, Fi- gure 54,635 c (S) t 54,646. Column of Glass Plate, with mount and haft t 54,647. — idem, smaller, Fi- gure 54,635 c (G) 1. 2. 0 1. 2. 0 1. 2. 0 — 0. 16. 0 2. 0. 0 560 Paalzow Optical Benches. No. 5464S — 54 653. 1 : 3. 1234 A • « 54654. 1:4. 54655. 1:1. t 54,648. 2 Double-refracting Prisms 20 mm diameter, in one mount with haft t 54,649. -- 13.5 mm diameter, Fi- gure 54,635 b (P) and 54,635 d (P) t 54,628. Complete Soleil Wedge Com- pensation 1 54,650. Right- and Left-rotating quartz plate, mounted in cork For large Paalzow Bench No. 54,631 For small Paalzow Bench No. 51,635 £ s. d. 3. 10. 0 — 2. 5. 0 6. 10. 0 6. 10. 0 0. 15. 0 15. 0 1 54,651. Small Window, half red, half blue glass t 54,652. Nicol with sharp edges for making the Lippich polariser, with suitable mount for the wedge compensation .... 1 54,653. Observation Tube, with haft, Figure, for filling with rotating solutions . . . For large Paalzow Benth No. 54,634 £ 0. d. 0 For small Paalzow Bench No, 64,885 £ s. d. «. 7. 0 1. 5. 0 1. 5. 0 0. 18. 0 0. 18. 0 Polarisation Apparatus for the Paalzow Optical Bench. £ s. d. t 54,654. 8 Rapidly Annealed Glasses of different shapes, Figure 2. 10. 0 t 54,655. 2 Crossed, Annealed Glasses in cork mount, Figure 0. 10. 0 1 54,656. Rock Crystal 0. 6. 0 t 54,657. Aragonite 0. 8. 0 1 54,658. Calc-spar 0. 6. 0 t 54,659. Gypsum with movable hyperbolae . . t 54,660. 2 Gypsum Plates for complementary colours, mounted in cork. Each £ 0. 3. 6 t 54,661. —idem, V4 wave length. Each £0.4.0 t 54,662. 2 Gypsum Figures, star and butterfly Further preparations listed on pp. 564 to 567. £ s. d. 0. 7. 0 0. 7. 0. 8. 1. 10. Auxiliary Apparatus for Experiments on Spectrum Phenomena, Fig. 54 635 e. t 50,986. Adjustable Gap, with micrometer screw, £ s. d. Fig. 54,635 e (F) and 50,986, p. 176, with round screen and haft 1. 8. 0 50,988a. — idem, with iris diaphragm . . 2. 16. 0 t 54,663. Cylinder Lens with screen and haft . 0. 15. 0 f 50,982. Collimator Lens with diaphragm and haft, Fig. 54,635 e (C) 0. 18. 0 54,664. Flint Glass Prism, 27 mm high ... 0. 10. 0 1 54,022. Wernicke's Liquid Prism, 20 mm aperture 2. 15. 0 54.028. — idem, built round, can be taken apart for cleaning, 30 mm 5. 0. 0 54.029. Direct-vision Prism after Koenigs- berger, 25 mm aperture 1. 10. 0 Liquid Prisms and Direct- vision Prisms (com- pound): see Nos. 54,022/059, p. 502. 54,042. Direct-vision Prisms, consisting of £ s. d. 2 crown glass and 1 flint glass prism, 20 mm high, without mount 2. 0. 0 54,052. — idem, consisting of 3 crown glass and 2 flint glass prisms, 38 mm side, 180 mm long, without mount, for placing on stage No. 54,665 8. 0. o f 54,665. Stage for preceding prisms, with rotary plate and haft 0. 10. 0 54,666. Direct - vision compound Prism as No. 54,052, quintuple, 38 mm side, hi mount with haft, Fig. 54,635e (D) . . . 9.10 0 t 54, 180. Absorption Box, Fig. 54,180, p. 516, 55 x 35 x 10 mm inside 0. 3. 0 Auxiliary Apparatus for Experiments on Microscopic Phenomena, Fig. 54 635 f. 1 51,048. Projection Microscope, Fig. 54,635f £ s. d. (M) and 51,048, p. 183, with object holder, rack and fine motion and condenser lens, without objective 4. 0. 0 Objectives for above: see Nos. 51,049 — 51,i>.~>3. t Collection of Microscopical Specimens for School Use: see Nos. 51,062 and 51.O63. p. 184. Auxiliary Apparatus for Experiments on Interference and Diffraction for the large Optical Bench No. 54634. 54,668. Complete Installation for Interference £ s. d. and Diffraction Experiments, I-'ig. r>4..y»

aiv for carrying out I lie experiments. gap with screw adjustment, 1 rotary £ ». double grating on glass, 3 screens for taking 12 diaphragms IS. o. lie the construction of the diaphragm^ supplied and of (lit- phenomena obtained by t lie same, flirt her part iciilars will be loutxi in the optical bench for interference and rl. 5276. 295. 298. No. 54 673. Technical Polarisation Apparatus. 561 54 670, 54 684. 1 : 6. 54 672. 1 = 6. diffraction experiments under No. 54,540; £ s. d. the set there mentioned comprises a com- plete and independent bench. As to the employment of device No. 54,668 with a small Paalzow Bench, see remark under No. 54,635. 54.523. Interference Mirror after Fresnel, Fig: 54,523, p. 545, with parallel micro- meter motion, micrometer screw with drum and graduation, on stand, carefully constructed 7. 0. 0 54.524. — i d e in, without parallel micro- meter motion 4. 16. 0 54,669. Complete Installation for setting up the Diffraction Chromoscope on the Paalzow £ s. d. Optical Bench, fitting the large Optical Bench No. 54,634 or the small bench No. 54,635 with extension. Given in are 6 image plates with, grating images after Wood, size of images about 6.5 cm . . 8. 0. 0 The outfit comprises 1 screening fold- ing box with one simple gap, 1 photo holder with change frame, 1 bi-convex lens, 1 gap adjustable as regards height and width and 1 achromatic objective with up-and- down adjustment. Further details as to the Diffraction Chromoscope given on p. 185, No. 51,066. Polarisation Apparatus for Technical Purposes. (Polariscopes.) 54,670. Polarisation Apparatus with Divided Circle, after Mitscherlich, Figure, with Laurent Polariser, for urine analyses, reading accurately to 0.1°, with observing tube 1.4 inni and one tube 94.7 mm long, without sodium lamp ........ ... £ s. d. 8. 5,0 By using the 189.4 mm long tube the angle of rotation in degrees gives direct the amount in grammes of dextrose contained in 100 com of the urine investigated. With rotations of more than 5° the sodium light must be purified by a light filter filled with potassium bicliromate solution (see next item). For gas sodium lamp see No. 54 684. • .54.."(, p. 560 0. lo.o These glasses show hyperbolae. .">l.704. 4 Coloured Plates, after Brezina, on interference phenomena in crystal plates, with text . . '. . . together 0. 16.0 Plate 1 shows a uniaxial crystal, ruby; plate 2 circular-polarising quartz: plates 3 and 4 a biaxial prismatic crystal ground perpendicular to optical centre line, in cross and hyperbola position (Cerussite Gypsum and Mica Preparations. 54,70."). Gypsum Wedge, 45 mm long, 1st to 2nd order 0. l.">.o .M.706. - - 1st to 3nd order 0.12.0 54,707. - - 1st to 5th order o. HI. 0 .M. "OH. Convex and Concave Gypsum Plates, Figure, in mount; can he rotated over each by means of rack and pinion for varying (lie colour ring 2. 0. 0 (1. 164!!. Hill. 1646. * (an be used with the Projection Apparatus 164S J>w lfi5J No. 54 759. Gypsum, Mica and Calc-spar Preparations. 565 54,709. Gypsum Plates of 1/1, 3/4, 9/4 wave length; thirteen different wave retardations can be £ s. d. produced with the same by alternating them; in round pasteboard mounts 0.15.0 Gypsum Figures, appearing in the different colours in polarised light. List No. 54,710 54,711 54,712 54,713 54,714 4 different-coloured Lamellae Cube Octahedron Star Butterfly £ 0.5.0 0.6.0 0.7.0 0.10.0 0.18.0 List No. 54,715 54,716 Flower Bouquet £ 1. 0. 0 1. 16. 0 54.717. Double Plate after Bravais 0. 10. 0 54.718. Small Gypsum Plate between two 1/1 mica plates, aperture 40 mm 0. 8. 0 54.719. - - idem, after von Mohl, collection of 8, comprising 4 gypsum plates, read first to fourth order, and 4 small mica plates of 1/8 — J/a wave-length 30 mm diameter . . 0.12.0 54.720. Single Gypsum Plate, in 1st order colours 0. 3. 0 54.721. - - in -colours of higher order 0. 3. 0 54.722. Quarter-wave Mica Plate, for investigating the character of double refraction in un- axial crystals, large and rectangular 0. 4. 0 51.723. Gypsum and Mica Combination, after Wright, giving the most beautiful phenomena, collection of 6 1. 4. 0 These preparations are only suitable for Polarisation Apparatus No. 54,618. 54.724. Mica Combinations after Norrenberg, for shewing how uniaxial mica is formed out of biaxial, collection of 6 pieces 1. 4. 0 54.725. - - in a preparation with mica segments crossed at right angles 1. 6. 0 54.726. Uniaxial circular-polarising Mica Combinations after Eeusch, left and right rotating, crossed at an angle of 60° Per pair 1. 4. 0 Calc-spar Preparations. 54.693. Calc-spar Plate and Glass Plate with lettering, see Fig. 54,693, p. 563 0. 16. 0 54,728. Calc-spar Prism for demonstrating decomposition and simultaneous double-refraction, showing two spectra (W. D. p. 452) 1. 0. 0 Nicol Prisms, with oblique end surfaces: List No. 54,729 54,730 54,731 54,732 54,733 54,734 54,735 54,736 Side mm 4 5 6 7 8 9 10 11 £ 0. 4. 0 0. 5. 0 0. 6. 0 0. 7. 0 0. 8. 0 0. 9. 0 0. 10. 0 0. 12. 0 List No. 54,737 54,738 54,739 54,740 54,741 54,742 54,743 Side mm 12 13 14 15 16 18 20 £ 0. 14. 0 0. 16. 0 1. 0. 0 1. 4. 0 1. 10. 0 2—2. 10. 0 3-3. 10. 0 The length 01 the prisms is about 2'/2 times the length of side. Prices for larger Nicols quoted on application. Glan-Thompson Prisms, with perpendicular end surfaces: List No. 54,744 54,745 54,746 54,747 54,748 54,749 54,750 54.751 54,752 54,753 Length mm 15 18 20 22 24 26 28 30 35 40 £ 0. 10. 0 0. 14. 0 0. 18. 0 1. 4. 0 1. 12. 0 2. 0. 0 2. 10. 0 3. 5. 0 5. 10. 0 8. 0. 0 The width is approximately hal! the length of the prism. The prices for prisms above 24 mm length fluctuate. Mounts for Nicol Prisms with divided circle on stand, Figure. List No. 54,754 54,755 For Nicols to 20 35 mm £ 2. 0. 0 2. 10. 0 54,756. Senarmont's Prism, made up of two calc-spar prisms (M. P. TI, 1, Fig. 711 [689]). I Prices according to size £ 1. 4. 0 to 2. 0. 0 Foucault Prisms (M. P. II, 1, Fig. 717 [695]), without cement, with air stratum: List No. 54,757 54,758 54,759 Side mm £ 20 1. 10. 0 2. 10. 0 30 3. 15. 0 566 Gale-spar and Quartz Preparations. No. 54 760 — 54 776. 1 : 2. 54777. 3. 54 785. Clan's Prisms (M. P. II, 1, Fig. 854 [1018]), with air stratum, without cement, optical axis parallel to refracting edge, end surfaces perpendicular to direction of rays: List No. 54,760 54,761 54,762 Free Aperture 12 16 20 mm £ 1.4.0 1.16.0 3.6.0 54.763. Wild's Double Plate 54.764. Calderon's Double Plate 54.765. Three Different Calc-spar Rhombohedra, Figure, with 6, 8 and 10 polished sur- faces, 20 mm side, in case Rhombohedra with the 6 natural cleavage surfaces, all 6 surfaces polished: List No. 54,766 54,767 54,768 Side mm 20 25 27 £ 0.16.0 1.6.0 1.15.0 - idem, also having two surfaces (ground and polished) perpendicular to the axis (8 polished surfaces). List No. 54,769 54,770 54,771 Side mm 20 25 27 £ 1.0.0 1.12.0 2.5.0 - idem, each having in addition two ground and polished surfaces perpendicular and parallel to the axis (10 polished surfaces). List No. 54,772 54,773 54,774 Side mm 20 25 27 £ 1.4.0 1.16.0 2.10.0 54.775. Calc-spar Cube, ground perpendicular and parallel to the axis 54.776. Calc-spar Plate between two Glass Prisms, Figure, shewing from one side the ring system and from the other double-refraction 52.224. Press for producing the sliding surfaces in calc-spar and rock salt, after Reusch, with preparations 52.225. Pressed and unpressed Preparations, singly £ 0. 2. 6 to 52.226. Press after Baumliauer, for producing calc-spar doublets . 54.777. 2 Large Calc-spar Rhombohedra on stands, Figure, in mount, rotary, approx. 25 mm side, for demonstrating all phenomena of double-refraction and polarisation peculiar to calc-spar Quartz Preparations. Quartz and Rock Crystal Prisms: sec Nos. 53, 975 — 53,986. Quartz Lenses, bi-c 0.15.0 1.0.0 1.5.0 1.10.0 2.0.0 List No. Diameter inn; £ 54,78/5. Double Plate, of right and left rotating quart/, 54,784. Bertrand's quadruple Quartz Plate 6. 0.0 0. 1L'. (I 1. -4.0 CI. 1858, 3873, 1058', lii.v.l. No. 54 792. Heat. 567 54 787. 1 : 6. 54786. 1:10 54788. 1:3. 54 789. 1 : 3. 54 791. 1 : 10. Heat. General. Thermal Expansion. 52,146. Molecule Model after Korner Fig. 54 216, p. 301, for explaining heat and its gene- ration by impact or friction (Fr. Phys. Techn. I, 2, Fig. 3899) 54,785. Brass Sphere with Ring, after S'Gravesande, Figure, for showing the expansion of solids by heat and contraction by cooling (W. D. Fig. 324 [306]), diameter of sphere 24 mm 54,786. - - idem, larger. Figure, with sphere 75 mm diameter 54,787. Brass Sphere on stem, Figure, with small tripod having a circular opening, for the same experiment * 54,788. Glass Sphere with tube closed at top, for showing the expansion of liquids, Figure, filled with coloured petroleum (W. D. Fig. 326 [308]) * 54,789. Glass Sphere with Capillary Tube open at top, Figure (Gan.-Man. Fig. 462; Gan.- Eein. Fig. 300) * 54,790. - - idem, without filling, for use for demonstrating expansion of air when a mercury thread is introduced (Gan.-Man. Fig. 463; Gan.-Rein. Fig. 301) 54.791. Square formed of Tubes, with two open limbs, Figure, for the expansion of liquids If the square of tubes is nearly filled with coloured water and one limb heated by a spirit lamp the water rises in this limb. 54.792. Air Thermoscope after Galilei (M. P., 10th Edn., Ill, p. 6; Meyer, Naturlehre, Fig. 11) ci. £ s. d. 1.10.0 0. 5.0 1. 8.0 0. 8.0 0. 1.8 0. 1.8 0. 1.8 0. 3.0 0. 2/8 ( 'an be used with the Projection Apparatus. 6078, 3410, 354, 355, 5798. 568 Heat. No. 54 793 — A). 54 795. 1 : 8. 54 799. 1 : 8. 54 802. 1 : 5. 54 800. 1 : 8. 54.793. Thermoscope after Drebbel. for showing the expansion of gases, Figure, consisting of a bulb, with tube attached, the former half-filled with a liquid, length of tube 75 cm, with graduation (Fr. Phys. Techn. I, 2, Fig. 2848) ................ 54.794. Tyndall's Apparatus for showing the Expansion of Gases, F i g u r e (Tyndall, Die Warme. Fig. 43, 1894) ............................. Prom the boiling fla'jk, tilled with air, a small tube leads into a wider, shortened barometer tube (to be filled witfi coloured water) clamped on the same stand. If the air in the flask is heated it expands and rises in bubbles into the barometer tube. 54.795. Contraction Apparatus alter Tyndall, Figure, for demonstrating expansion by heating and elementary force on contraction by cooling (M. P. II, Figs. 34 and 35 [II. 2, Figs. 32 and 33]), with 12 cast-iron rods . . . . ....... " ...... '. . A 9 mm thick cast-iron rod is fractured by the roiicra -lion of a thick square-section rod after heating. For Bunsen Burners and Heating Stand, see following items. 54.796. 4 Bunsen Burners, arranged in a row, for heating the iron bar ................. "i4.7!(ti a. Simple Stand on which to set the iron bar while heating, together with wire stirrup for supporting the bar ........................................... •M.T'.t". Contraction Apparatus with Fletcher Burner, for use without heating stand . . . 54.798. Contraction Apparatus after Tyndall, as No. 54,795, but double the size ..... 51.799. Pyrometer. F i g u r e (Kr. phys. Techn. I, 2. Fig. 2990 | I, Fig. 337]), for demonstrating linear expansion, with three bars of brass, iron and /inc; with gas burner, graduation £ s. d. 0.10.0 1. 0.0 n ;,„„ mm (dan. -Man. Fig. 460: Can. -Rein. Fig. 298) 54.800. --id e m, F i g u r e, with Spirit Burner 54.801. 3 Bars for .Nos. 54,799 and 54,800, of Copper, German Silver, and Aluminium 01. Compensating Pendulums: see Nos. 01,01)0,7 and ol,7U3. 5772. liifit. 1667 ', 0. 14. 0 (I. 14. u 0. 4. II 1. 0.0 1.16.0 1. 8.0 1. 8.0 0. 3.0 618*, 5413, 1667. No. 54 806. Thermal Expansion. 569 54 803. 1 : 6. 54 805. 1 : 6. 54 806. 1:11. 54.802. Pyrometer with 2 Pointers, F i » u r e, for comparing the expansion of tw > bars of iron and zinc 54.803. Pyrometer, steam heated, F i g u r e, with tubes of brass, copper and iron . . . 51,285. Small Weinhold Steam Boiler, Fig. 51,285, p. 213 (W. D. Pig. 49 [45]), for producing steam at boiling temperature and higher, of sheet brass 54,804. — i d e ni, with tripod £ s. d. 2.10.0 1.16.0 0. 16. 0 1. 3. 0 5.10.0 54.805. Drum Pyrometer, F i g u r e, with thermometer and spirit lamp (Fr. phys. Techn. I. 2, Fig. 2994) The six bars of copper, brass, iron, zinc, aluminium and German silver respectively, contained in a water bath, can be successively rotated under a "feeler lever". The bars are adjustable by micrometer screws. The indicating mechanism is very sensitive, the scale peimitting of reading direct to '/no mm- The box has a lateral copper tube for heating and a stirring device. 54.806. Apparatus for measuring the linear Expansion of Rigid Bodies, after Weinhold. Figure (W. D. Fig. 334 [315]), for objective demonstration, with three lubes of brass, iron, and glass respectively, the tubes heated by steam direct reading on glass scale f 2. 10. 0 53,195. Drawn Brass Tube, after Eebenstoiff, for thermal expansion in large dimensions (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 248), also for conserving the acoustic intensity without lateral expansion (Ztschr. f. d. phys. u. chem. U. 19, 1906, p. 279); total length 4 m, 20 mm wide, in two parts, for steam-heating in the heat experiment 0. 10. 0 * Can be used with the Projection Apparatus. Cl. 6143, 6141, 6178. 570 Heat. No. 54807 — 54 808. 1 54 810. 1 : 6. 54 812. 1 ; 20. 54,807. Tube Expansion Apparatus after Friedr. C. G. Miiller (M. T. Figs. 101 and 10-'), suitable for observations at great distances £ s. d. 3.12.0 54.808. Apparatus for the Linear Expansion of Steel and Zinc after Borda (Dulong and Petit), by the differential method, Figure, with two bars 120 cm lotiu. '_'."> mm wide, and 4 mm thick (M. P. Ill, Fig. 32 [II, 2, Fig. 30 ]) . ... j 3.12. 0 54.809. - - ide m, smaller, with 6 bars of iron, brass, copper, /inc. aluminium, and (iernian Silver, Figure, with two thermometers to + 240°C. and Stirrer 6. 0. 0 The apparatus consists of a copper hov in which the bars to be compared rest on fillets. These bars arc pierced at one end so as to enable them to be firmly connected by a bolt; at their tree ends they ca'Tv rectangular attachments allowing them to project out of the bath as shown in the Figure. On the upper sides of these angle pieces are placed graduations. Accurate reading with a vcrni'T can lie made since the comparison bar (of iron) ha- a millimetre graduation -J(I mm long and the ba-s to be compared are scaled ]!> in long with 20 divisions. Cl. 1673. 1074, 3411, Ifl77. No. 54 814. Coefficient of Expansion. 571 54 813. 1 : 6. 54 814. 1 : 6. 54,810. Apparatus for determining the Linear Expansion Coefficient of Bars, after Lavoisier and Laplace, for mirror reading, Figure, with heating apparatus and water jacket, with inlet pnd outlet for cooling the frame (W. u. E. phys. Prakt., Fig. 91; M. P., 9th Edn., II, 2, Figs. 28 and 29) Given in as test pieces are bars, 0.5 m long, of copper, iron, glass, and ebonite (the latter resting on a somewhat shorter glass rod). 54,811. - - idem, with Micrometer Reading, bath and one thermometer to 250° C. . Figure, with heating apparatus, copper The apparatus is easy to manipulate. The alterations in length are read off on the micrometer direct to 0.01 mm. We supply as test pieces rods, 0.5 m long, of iron, copper, zinc, brass, glass, and aluminium. 54.812. Apparatus for shewing the Contraction of an expanded Rubber Tube by Heat, Figure (W. D., Figs. 335, 336 B [316, 317 B]), comprising rubber tubing with hooks at the ends, balance pan, and steam conduit pipe The accessories illustrated, i. e., steam boiler with stand, tackle, and weights, are not included in the price. Price of Boiler and Stand £ 1. 13. 6; Balance Pan No. 52,216, £ 0. 6. 0. 54.813. Dilatometer. Figure (Chwolson, Lehrb. d. Phys., Vol. Ill, Fig. 39), for deter- mining the cubical expansion coefficient of solids, with iron bar 100 g weight . . . 54.814. Weight Dilatometer, Figure, for determining the cubical expansion coefficient of liquids and glass (W. u. E. phys. Prakt., Fig. 92) £ s. d. 7.10.0 12. 0.0 1. 6.0 0.12.0 0.10.0 Cl. 1676, 3963, 1679. 572 Heat. No. 54 815 — 54816. 1:5. 54815. 1 = 2. 54819. 1:3. 54817. 1 : 3. 54821. 1 : 7. 54822. 1 : 5. 54823. 1 : 54.815. Weight Dilatometer (Weight Thermometer), Figure, for the same purpose, with £ s. d. stand and receiving vessel (W. u. E. phys. Prakt., Fig. 93; cf. Chwolson, Physik, pp. 58 and 95) 0.16.0 The vessel D is filled with mercury by the aid of the air pump by plunging it completely in a second vessel containing mercury. When heated in an air bath the mercury passes into the vessel V. 54.816. - - idem, without stand or catching vessel, Figure (M. P. Ill, Fig. 50 [II, 2, Fig. 48]), without mercury 0. 3. 0 54.817. - - idem, with straight outflow tube and ground-on cap, Figure (M. P. Ill, Fig. 51 [II, 2, Fig. 49]), without mercury 0.5.0 54.818. 3 Expansion Flasks with very plain graduation on neck, 100 ccm (M. T., Fig. 103) 0. 4.0 * 54,819. Projection Water Dilatometer, Figure, simply and conveniently arranged (Fr. phys. Techn. I, 2, Fig. 3041) 0. 7. 0 54.820. Compensated Water Dilatometer after Xoack (M. T., p. Ii5; /tschr. f. d. phys. u. chem. V. 2, 1S8!>. n. 159); the expansion of the vessel is compensated by mercury; with stirring device acting by blowing air in 2. 0. 0 54.821. — idem, after I'oske, Figure (Hofler-Poske, Oberstnfe, Fig. 283 and p. 89:!; Ztschr. f. d. phys. u. chem. V. 2. 1888, p. 12) 1. 5. 0 54.822. -- idem, after (irimsehl-Kebensrorff, Figure (Ztschr. f. d. phys. u. chem. U. 18, 1905, p. 92), with stirrer. The expansion of the glass vessel is compensated by a corresponding quantity of air | 0. 18. 0 ci. ono, 1680,6111.6193,5715, 4703,6142. * Can be used with the Projection Apparatus. No. 54 829. Dilatometers. Expansion Anomaly of Water. 573 54825. 1:3. 54827. 1:5. 52549. 1 : 5. 54.823. Glass Cylinder with Heating Device, Figure. (1) for investigating the stratifi- cation of liquid masses in accordance with their specific gravity; (2) the circulation of water, in which the thermometer shows a lower temperature in spite of its proximity to the thermal source; (3) convection of water. With two thermometers 54.824. Glass Cylinder with Cooling Ring, after Hope, Figure, for investigating the strati- fication of aqueous masses according to their specific gravity and for determining maximum density (Gan.-Man., Fig. 478; Gan.-Eein., Fig. 323), for cooling by ice . . 54.825. 2 Thermometers with annular, horizontally arranged Vessels, after Weinhold, Figure, for measuring the temperature-differences in different layers of water, particularly also for measuring the temperature in the lower aqueous layers of a vessel on reaching maxi- mum density (\V. D., 4th Edn., Fig. 339) The attainment of maximum density is determined by the Looser or Kolbe Thermoscope (or in another manner, e. g. with Weinhold's Apparatus No. 54,826) and the temperature measured in the undermost and uppermost aqueous layers. The thermometer intended for the lower aqueous layer has a capillary tube 20 cm long beetween vessel and scale in order that the readings of the instrument may not be appreciably influenced by the temperature of the upper aqueous layers. The thermometers are alcohol-filled, 1" = 5 mm length. 54,826. Thermoscope after Weinhold, Water (W. D., 2nd Edn., p. 304) Figure, for 'measuring the maximum Density of * .VI, 827. Apparatus after Wais, Figure, for shewing the Expansion Anomaly of Water by cooling by means of ether evaporation; wide test tube with water thermoscope, inlet and outlet tube for gas or air blowing, and piece inserted having narrow test tube. Can be used with the Projection Apparatus (Ztschr. f. d. phys. u. chem. U. 13, 1900, p. 219) 52,549. Hydrometer, very sensitive, F i g u r e, for measuring the Density of Water at tem- peratures between 0° and 25° C. and for proving Maximum Density: large pattern . Cold-water Floats: see Nos. .->:>, 526 and 52,528, p. 345. :>I.X29. Lantern Slide of the curve of maximum density of water in relation to that of glass (W. D., Fig. 340 [320]) £ s. d. 1. 4.0 0.16.0 1. 5.0 0. 6.0 0. 8.0 0.15.0 0. 1.6 * Can be used with the Projection Apparatus. Cl. 6144. 3753, 1884, 359, 787. 574 Heat. No. 54 830 — 548 -A. 30. 1:4. rf" +- 54835. 1 : 12. 54 832. 1 : 5. 54 836. 1 : 15. 54.830. Apparatus after Weinhold, Figure, for projecting the phenomena of the freezing of water and melting of ice, also the behaviour of water on boiling (VV. D. Figs. 331 — 333 [312 — 314]), consisting of two glass apparatus, one lead pipe cooling coil and one pro- jection thermometer 54.831. Glass Tube for showing the Circulation of Water, Figure (W. D., Fig. 341 [321]) * 54,832. - - idem, small, for use with the Projection Lantern, on heating stand, Figure 54.833. Overflow Apparatus after Schaffer, for showing the motion of unequally heated water, of glass, with stand (Bohn, Physikal. App. u. Versuche, No. 254; M. T. p. 145) . . 54.834. Hot Water Heating, model of glass, on stand, after Schaffer (Bohn. Physikal. App. u. Versuche, No. 255; M. T. p. 145) :> l .S3.r>. Apparatus for showing the Expansion of Mercury by means of the Alteration in Level in communicating Tubes, Figure (W. D. Fig. 337 [318]), water-cooled; suitable for explaining the measurement of expansion coefficient after Dulong-Petit-Reguault . . 51,836. - - idem, after Dulong and Petit, Figure (M. P. Ill, Fig. 46 [II, 2, Fig. 44]; Gan.- Man., Fig. 477; Gan.-Rein., Fig. 328), with cathetometer The determination of the expansion of mercury is made by showing the change in height in communicating tubes when one tube is cooled and the other heated. The mercury levels are read on the cathetometer; the temperature is determined in the heating vessel by means of an air thermometer having a long air vessel. Freezing temperature is maintained in the cooling vessel by melting ice. The communicating tubes are constructed of steel tubing, the ends being formed of glass tubes inserted in stuffing boxes. The heating vessel is of copper, being provided with a heating jacket. 12 Bunsen burners projecting into this jacket heat the oil bath very uniformly to 280° C. in 8 — 10 minutes. The cooling vessel is in three portions which can easily be screwed apart for cleaning. With the aid of a gas regulator it is possible to maintain the temperature uniform for a long time. The overall height of the apparatus is 1.6 m and breadth 1 m. * 54,837. Apparatus after Eiihlmann, Figure, for showing the Expansion of Gases at constant pressure, for the Projection Lantern (W. D., Fig. 342 [322]) £ s. d. 0.14.0 0. 4.0 0. 8.0 0. 18.0 1.10.0 0.18.0 15. 0.0 0. 12. 0 54,838. Apparatus for determining the Expansion Coefficient of Gases at constant pressure (diiy-Lussac's Law), after Weinhold, Figure (\V. I)., 4.. Edn., Fig. 343) .... 1. HI. u With this apparatus the value of (lie coefficient of expansion is obtained iivcurn'oly to the 'J»ii significant figure (4'h decimal). * Can be used with the Projection Apparatus. Cl. 6192. 1689, 5888. 360. 1692. No. 54 841. Expansion of Liquids and Gases. 575 54 839. 1 : 9. 54 841. 1 : 8. 54,839. --idem, Figure, the gases heated by water vapour and by alcohol vapour, with cock for regulating the pressure (Fr. phys. Techn. I, 2, Fig. 2840) Further Apparatus for determining the Expansion Coefficient of Gases: see Nos. 52,706, 52,707, 52,812 and following items. •"> l.* -10. Apparatus for the Expansion of Gases at constant pressure, after Kegnault, Figure, for accurate measurements (M. P. Ill, Fig. 61 [II, 2, Fig. 59]) . Gas Dilatometer. after Gay-Lussac, Figure, for determining the Expansion of Gases at constant pressure (M. P. Ill, Fig. 58 [II, 2, Fig. 56]; Gan.-Eein., Fig. 324) £ s. d. 1. 7. 0 8. 0. 0 4. 0. 0 Cl. 6530, 4708, 1695, 3851, 4547. 576 Heat. No. .14 842 - 54842. 1:7. 54848. 1 : 6. 54 845. 1 : 7. 54 846. 1 : 4. 54847. 1:10. 54849. 1:8. 54850. 1 : 8. 54.842. Apparatus for determining the Coefficient of Expansion (pressure-increase Coefficient) £ *• i] of Gases at constant volume. Figure (W. D., Fig. 344 [324]) 0. 10. 0 The vessel can also be used for Apparatus N'o. 52,811 in order to admit of the latter being used as an air thermometer: see Fig. 52,81 1, p. 377. 54.843. Large Glass Flask for determining the Coefficient of Expansion of Air, also the Specific Gravity, with glass stopcock (4 litres capacity) 1. o. o t'f. Fig. 53,034, p. 402. 53,033. Glass Sphere with two Stopcocks, for the same purpose (Fr. phys. Teclm. I, 2, Fig. 2837) 0. 10. 0 54.844. Gas Dilatometer, after Friedr. C. G. Miiller (M. T. Fig. 104), consisting of boiling flask (1 litre), large beaker, glass cylinder, calibrated bell, 2 iudiarubber stoppers, 3 glass tubes with stopcocks and rubber tubing o. 15. 0 53.121. Windmill for showing the Motion of Heated Air (M. T. Fig. 105) 0. 3.0 Thermometers, Pyrometers, and Thermoscopes. 5I.SJ5. Thermometer Tube, with bulb blown on, F i g u r e. so as to fill and make a thermo- meter oneself for 0 — 100" ('. A diagram of I he scale is appended to the tube (dan. -.Man., Fig. 480; Can.- Rein.. Fig. 302) 0. 0. 6 5i.x if>. Thermometer with ground milk-glass plate, Figure o. 2. o The thermometer is mercury filled and ha- a ground milk-glass plate the rough side being in front. The apparatus is intended for demonstration experiments, being ungraduated : tin- yraduation can be attached by the- lecturer as occasion demand- and removed a^uin. The thermometer is dimensioned for 0—1 '' C. 5I.X.J7. The Thermometer in 7 Stages of Construction, Figu re; 2 half-finished Maximum Thermometers and a high-range Thermometer in three stages of construction .... 1.10.0 54,8-is. Thermometer with 3 Scales on wood. Figu re, 350 x 50 mm, graduations in Reaumur. Centigrade and Fahrenheit degrees, from --20" to -100" Centigrade 0. 2.0 cl. ss«. r.i.-ifi. 1697, 1698, 4195. 3412, 6120. No. 54 863. Thermometers. 577 54852. 2:7. 54853. 1:5. 54 854. 1 : 4. 1 i ! g . L i i [ ' •• If . 9 » ; 8 1 : ; I ^ g 1 1 P i P E w i \ • i 1! ¥ * 54856. 54858. 54859. 54860. 54861. 54862. 1:9. 1:9. 1:9. 1:9. 1:9. 1:9. £ s. d. 54.849. Demonstration Thermometer, Figure, filled with sulphuric acid, with plain black and white scale, in Vi0* milk glass scale, visible at a distance, range — 15° to -f- 100° C., 1 m long- 0.12.0 54.850. Demonstration Thermometer after Friedr. C. G. Mtiller, with paper scale and coloured graduation, Figure, divided every 5°, filled with sulphuric acid, range — 20° to + 150° C., 0.5 m long 0.6.0 These thermometers are of oval section, whereby the reflex action prevalent in a tube of circular section is avoidc:!. 54.851. -- idem, 1.00 m long, graduated from --20° to +150° C 0.12.0 54.852. Water Thermometer, without mount, Figure, open scale (M. P., p. 145) ... 0. 4. 6 54.853. Water Thermometer and Mercury Thermometer on one board, Figure, for showing the unequal expansion of water 0. 6. 0 * 54,854. 3 small Thermometers, Figure, for objectively demonstrating the variation in expansion of different liquids, filled with mercury, sulphuric acid and alcohol respec- tively, on stand « . ff. 16. 0 The thermometers have vessels of the same size and capillaries of the same width; the scales vary in size corresponding to the different expansions. * 54,855. Projection Thermometer, divided from - - 40° to + 50° C. in whole degrees, with transparent glass scale and reversed figures 0. 6. 0 * 54,856. Projection Thermometer, graduated from - - 10° to + 160° C. in whole degrees, cf. j Figure, with transparent glass scale and reversed figures, without stand . . . . ; 0. 6. 0 * .~>4,857~Projection Thermometer with*" long stem, for calorimetric and similar experiments, • divided from 0° to -|- 30° C. in 1/10°, with reversed figures . . 0. 12. 0 54,858 . Simplejcyh'ndrical Thermometer, __F_i_ g u r_e, for 0° to 100° C., with paper scale . 0. l.o 54,85!). Cylindrical Thermometer with milk glass scale from — 20° to + 360° C., F i g u r e 0. 3. 0 54.860. --idem, with scale etched on tube, — 20° to + 360° C., 450 mm long, 6—7 mm i diameter, Figure 0. 4. 0 51.861. Cylindrical Thermometer, 0.5 m long, range from — 10° to + 100° C., in 0.1°, divided on milk glass, Figure i 0.10.0 5 1 sii'j. Cylindrical Thermometer for calorimetric Work, Figure, from --10° to -- 40° C., divided in 0.1° 0. 5. 0 54,863. - - id e m, for very accurate work between 15° and 26° C., divided in 0.02°, with the value for wain given 1.10.0 The thermometer has a quite cylindrical lumen, so that the readings do not vary among each other by more than ;v thousandth of their value. # Can lie used with the Projection Apparatus. Cl. 1700, 1701, 5293, 6150, 6149, 6148, 6146, 6147, 6145. 37 578 Thennometry. No. 54 864 — 54 876. 1 : 6. 54867. 1:6. 54871. 1:5. 54872. 1 = 6. 54875. 1:10. 54 877. 1 : 3. 54.864. Cylindrical Thermometer for temperatures of 0° to +550°C., filled with carbonic acid * gas over the mercury at 20 atmospheres 1.10.0 54.865. Cylindrical Thermometer for temperatures of — 100° to -f- 50° C., for cold mixtures, divided in whole degrees 1. 5. o 54.866. Cylindrical Thermometer for temperatures of — 200° to 0° C., for cold mixtures . 1. 8. n 54.867. Standard Thermometer, Figure, from --5° to 4-50° C., divided in 1/m°, with calibrated tube, with glass lug at top, in wood box o. 15. o 54.868. - - idem, tested every 10°, with Test Certificate of the Physikalisch-Technische Eeichsanstalt, Charlottenburg 1. 0.0 54.869. Standard Thermometer from --5° to +100° C., constructed as No. 54,867 ... 1. o. o 54.870. -- idem, tested every 10°, with Test Certificate of the Eeichsanstalt, Char- lottenburg 1. 10. o 54.871. Thermometer on Wood Board, for schools, Figure, from --40° to +50° C., 30 cm long Each o. 1. o Per dozen <>. Hi. o 54.872. Thermometer for screwing to the window, Figure, round, 25 cm long, with Centi- grade graduation from --40° to -f- 50° C., with porcelain scale enclosed in glass tube. with brass fittings 0. I. (» 54.873. Clinical Thermometer (M. T., p. 138) 0. 3. 0 54.874. Metastatic Thermometer of Walferdin (Beckmann's Thermometer), for accurately measuring small temperature differences, for comparison with a standard thermometer (M. P. Ill, Fig. 16) 1. Hi. i» '•1,874 a. Hypsometric Thermometer (for altitude measurements), 22 cm long, from 87° — 102° ( '. graduated in l/20° 1. 1 •'>.(> 54871 b. -- idem, 50 cm long, from 92° to' 102° C., divided in Vso° 2. 6. 0 54.875. Long Stem Thermometer with metal mount, Figure, range 0° to 200° C., length of immersion tube 60 cm 1. d. d .'•1.876. Angle Thermometer in Metal Mount, F i gu re, range 0° to 200° ('., with side tube 24 cm long .1. o. o Thermometers Nos. 54,875 and 54,876 are arranged in such manner that the mercury bulb i in the inside of a boiler, box, etc.. while the scale (surrounded l>y a metal mount to protect it from knnckl) is placed outside t lie vessel in question. Cl. 1711. 170'A 61J5, 0157. 1710, 1703. Xo. 54 885. Maximum and Minimum Thermometers. Recording Thermometers. 579 54878. 1 : 5. 54880. 1:5. 54 881. 1 : 5. 54879. 1:5. 54 882. 1 : 5. 54 884. 1 : 5. 54885. 1:6. 54.877. 1 Maximum and 1 Minimum Thermometer, Figure, divided in, Y8°, with gradua- £ s. d. tion etched on glass. Both in one case 0. 18. 0 54.878. Thermometrograph after Six, Figure, on. wood board, 320x65 mm, with Centi- grade graduation from — 35° to + 50° C 0. 6. 0 54.879. - - idem, after Six, with milk glass scale, in copper chamber, Figure, 320 X60 mm, with Centigrade graduation from — 35° to -(- 50° C 0.12.0 54 880. Minimum Thermometer, Figure, with porcelain scale in mahogany frame ... 0. 15. 0 54 881. Maximum Thermometer, Figure, same pattern as above 0. 15. 0 54.882. Thermograph, Figure, with 14-day movement and 2 drums so that a whole week's diagram can be seen, with walnut case 8. 15. 0 54.883. -- idem, with electric contacts for maximum and minimum reports 9.10.0 54.884. Small Thermograph, Figure, with scale from — 10° to -f- 40° C., in mahogany case 5. 0.0 54,885. Thermograph, Figure, with flexible connecting tube 2 m long, for determining temperatures of liquids and for observing the temperature in rooms and in the open ,10. 0. 0 C1. 6153, 6154, 6151, 6152, 6533, 6534, 17,?2. 37* 580 Thermometry. No. 54 886 — 54886. 1:4. 54887B. 1:7. 54 887 A. 1:6. 54888. I:.',. 54 889. I : 10. 54 890. 1 : 8. 54 893. 1 : 6. 54,886. Electric contact Thermometer from --30° to +80° C., cf. Figure, with double * •• ''• tnbr with platinum wires and six terminals, making contact every l_'(i". commencing at --20° C., for maximum and minimum registrations 1. l.o .>l.s,s7. Boiling point Determination Apparatus for Thermometers, Figs. A and B (M. P. II, 2, Fig. 4; W. E. phys. I'rakt., Fig. 95; (.Jan. -Man. Fig. 468), with simple thermometer 0. Hi. o I'm. A is a view and Fij;. B a section of the apparatus. 54.888. -- idem, Figure, for travelling purposes, eollapsible. ran lie used as a Hypso- meter, without thermometer, with spirit lamp for attaching -'. s. o 54.889. Freezing Point Determination Apparatus, Figure, with waste tor the water (dan.- Man. Fig. 466), without thermometer or catching vessel 0.10.0 Calibration Apparatus for Thermometers (Comparators) see p. L'L';>; Dividing Engines, p. -'US. CL 8309, 1T1S, 1713,1714. 1715,3938. Kiii. No. 54900. Freezing and Boiling Point Determination. Metalic Thermometers, Air Thermometers. 581 54 894. 1 : 2. 54 897. 1 : 3. 54 898. 1 : 5. 54900. 1:15. 54.890. Thermometer Testing Apparatus, Figure, Budberg's boiling tube with return flow cooling (Ztschr. f. Instrkde. 11, 1891, p. 1), without air chamber Thermometer Testing Apparatus, electrically heated, quoted for on application. Reading Microscopes for Thermometers, see p. 226. Thermo-Regulators, see p. 208. 54.891. Strips of Steel and Zinc, curling when heated .">4,X92. --idem, of Steel and Ebonite 54,893. Strips of Steel and Zinc, with pointer and scale, Figure £ s. d. 4.10.0 54.894. Metallic Thermometer, Figure, Swiss pattern (M. P. III., Fig. 39 [II, 2, Fig. 38]), with maximum and minimum pointers, very reliable ............... 54.895. -- idem, with electric contact, without maximum and minimum pointers . . . J.s'.iG. Metallic Thermometer after Breguet, Figure (M. P. Ill, Fig. 41 [II, 2, Fig. 39]), with platinum silver spiral, with connecting terminals for measuring weak galvanic currents ................................... -!, s'.(7. Metallic contact Thermometer, Figure, round pattern, 130 mm diameter, very sensitively constructed, with contacts for maximum and minimum registration, from - 20° to + 40° C. .............................. T.1.S98. -- idem, Figure, range 0° to 100° C 54,792. Air Thermometer after Galilei (M. P., 10th Edn. Ill, p. 6; Meyer, Natmi., Fig. 11) . 54,900. Air Thermometer after Eegnault, Figure (M. P. Ill, Figs. 71 and 72 [II, 2, Fig. 70]), with unscrewable air chamber, fittings well constructed of steel, wood frame Cl. 1722, 1721, 4008, 0. 3.0 0.16.0 1.16.0 2. 5.0 ! 2. 6.0 1.10.0 1.16.0 0. 2.8 4.10.0 5418, 1724. 582 Thermometry. No. 54 901 — 54 901. 1 : 16. 54 902. 1 : 12. 54903. 1:12. 54.901. Gas Thermometer after Chappuis, Figure (M. P. Ill, Fig. 79; Chwolson, Physik, £ s. d. Vol. Ill, Figs. 6 and 7), model of the Bureau International des poids et mesuros, Paris, with platinum capillary i!8. 0. o This apparatus is especially adapted for very accurate measurements; only two readings are necessary for the single temperature measurements so that the sources of error are not so great as in instruments which necessitate four reading*. The tubes are wide enough to exclude any error of capillarity. The readings are made by means of a cathetometer and with the aid of an accurate rule. 54.902. Air Thermometer after Jolly, Figure (M. P. Ill, Fig. 73 [II, 2, Fig. 72]), con- structed entirely of iron, steel stopcocks. The apparatus has a height of 1.6 m when the rule is not extended. All bare parts are heavily nickelled. The thermometer Chamber is filled with dried air 12. 0. 0 For filling, 5 kg mercury (£ 2. 0. 0) is necessary. 54.903. Air Thermometer after Jolly, Figure (M. P. Ill, Figs. 74 and 75 [II, 2, Fig. 73]), j with plate glass scale 5. 0. 0 54,904. Air Thermometer after Jolly, Figure (W. u. E., phys. Prakt., Fig. 52). with plate glass scale and micrometer adjustment for one limb r. I.'.HM;. Air Thermometer alter Berthelot-Alvergniat, Figure, on wood stand with fixed 0. 10. 0 scale 2. 5.0 r,.,,,r. Double-chamber Air Thermometer (Differential Air Thermometer), after I'laumller (M. P. Ill, Fig. 81 [II, 2, Fig. 80]). without stand 0. The two vessels eonlain air at different pressure, beiiij; exposed to I he same temperatures. 54,908. -- idem, on stand, with scale. Figure 1. 4.0 As air thermometers use may be made of the apparatus for Boyle's (Marriot.te's) Law alter Feilitzsch, Friedr. ('. 2,706 — 52,70*. ci. 5376, 1725. 1726. No 54910. Air Thermometers. 583 54 908. 1 : 8. 54906. 1:14. 54 909. 10. 54910. 1:11. 54,909. Self-correcting Air Thermometer after Prof. Friedr. C. G. Miiller, Figure (Ztschr. f. d. phys. u. chem. U. 8, p. 308; M. T., p. 139), on metal stand, wood parts of polished mahogany, rules of boxwood and celluloid, all parts most thoroughly constructed . . I1 Hll to be transported in the filled condition. sypkn £ s. d. 5.10.0 54,910. - - idem, simplified pattern, Figure, with scale visible at a distance, 1° about | 12 mm long (M. T., Fig. 97) j 2. 2. 0 C'l. 1727,5297, 1729, 1730, 5286. 584 Thermometry. No. 51911 — 54 911 A. 1:14. 54 911 B. 1:14. • 54912. 1 : :i. 54913. 1:3. 54.911. Demonstration Air Thermometer after Weinhold, Fig. A (looked at I'mni the front) £ s ''• and B (looked at from back (W. D., Figs. 345/7 [325/7]) 22. 0. 0 The temperature is adjusted automatically by a small electric motor which carries the mano- meter tube up and down. The thermometer chamber is connected to the manometer by a long flexil>l<- silver tube, the silver tube being protected from external damage by a rubber coating. The apparatus gives very reliable results. -" - F- • 54.912. Thermocouple (Electric Pyrometer), after Le Chatelier, F i g u r e, in conjunction with one of the Galvanometers Nos. 54,917/9, for use for temperatures to 900" C., with platinum and platinum-rhodium couple of 0.6 mm wires, with shielding and insulating tube of Marquardt porcelain and with steel sheath 130 cm long, for continuous measure- ments, provided with Test Certificate of the Physikalisch-Teclmische Keichsanstalt : without galvanometer ' !.">. ln.o 54.913. -- idem, for temperatures to 1500" C. (in conjunction with one of tin- galvano- meters Nos. 54920/2), with porcelain tube mounting, Figu re, with .Marquanlt por- celain tube 130 cm long projecting freely out of the iron lube; for continuous measure- ments, with Test Certificate of the Beichsanstalt ; without galvanometer !.">. lu.n All abrupt temperature variations or mechanical strains should be avoided. 54.914. -- idem, for temporary measurements of temperatures io 1400° C. (to be used in conjunction with one of the galvanometers Nos. f>4 9lii) •_'). with silica mounting which can be subjected to the most abrupt temperature changes. l.'iOemlong; \\ith Test Certificate of the Kcichsanstalt : without galvanometer 1. VI 0.0 cl. 1731'. 17:;,-. >;:,!•>. No. 54 927. Air Thermometers. Pyrometers. 585 54 916. 1 : 3. 54917. 1:4. 54 918. 1 : 5. 54 919. 1 : 4. 54,915. - - idem, 150 cm long, for temperatures to 1100° C., in refractory fireclay tubes (to be used in conjunction with one of the galvanometers Nos. 54,917/9); with Test Certi- ficate of the Physikalisch-Technische Eeichsanstalt ; without galvanometer £ s. a. 16. 10. 0 54,916. --idem, Figure, with small platinum tube of about 55 grammes weight in the lower part, for temperatures to 1600° C. (for use in conjunction with one of Ilic galvanometers Nos. 54,920/2). Extra price according to the prevalent price of platinum (without Galvanometer) £ 17. 10. 0 to 22. 10. 0 54,917. Galvanometer for Thermocouples Nos. 54,912 and 54,915, with temperature scale from 0° to 1100° C., Figure, with pivot bearing, portable in case 54.918. - - i d e m, with fibre suspension, Figure 54.919. - - idem, with perpendicular scale, Figure, wall pattern instrument .... 54.920. Galvanometer for Thermocouples Nos. 54,913, 54,914 and 54,916, with temperature scale from 0° to 1600° C., with pivot bearings, portable, in case 54,921. - - idem, with fibre suspension ."i-1, 922. -- idem, with vertical scale, wall pattern instrument 54,923. Electric Resistance Thermometer, Figure, for temperatures between — 200° and + 900° C., within the ranges named under No. 54,928, 20 cm long, can be used for distance reading, distance registration and registration in conjunction with one of the indicating apparatus mentioned further on The resistance consists of a fine platinum wire fused into quartz glass in such manner as to protect it entirely from external influences. The resistance wire takes up the external temperature very rapidly (more quickly, for instance, than a mercury thermometer); the thermometer is insensitive to abrup, temperature change owing to the excellent properties of the quartz glass. A complete installation consists of: (1) one of the thermometers Nos. 54,923/6; (2) an Indicator for stationary use No. 54,928 or 54,929, fitted perhaps with signalling device No. 54,930; or a portable Indicator No. 54,931 or 54,932; and (3) one or two Accumulators Nos. 54,936/7, according to the sen- sitivity desired; or a Compensator No. 54,938. If recording is desired, use should, be made of (4) :•, Recording Galvanometer No. 54,933. If a number of thermometers are to be connected to the measuiiii". arrangement, (5) a Plug Commutator No. 54,934 or 54,935 should be added. 11. 5.0 10. 10.0 11. 5.0 11. 5.0 10.10.0 11. 5.0 2. 10. 0 ."11.1124. Extending the Thermometer every 10 cm costs in addition 54,925. The same Thermometer with iron sheet, 50 cm long, with terminals on the por- celain head 0. 8.0 3. 0.0 54.926. Extending this Pattern every 50 cm 0. 6. 0 54.927. Test Certificate of the Physikalisch-Technische Eeichsanstalt for one Thermometer . j 0. 18. 0 Cl. 1737, 6540, 6547, 6518. 586 Thermometry. No. .'.4928 — 54 929 A. 1:5. 54 929 B. 1 : .5. 54 938. 1 : 5. 54941. 1:7. 54.928. Indicator for stationary use, cf. Fig. 54,929 A and B, for Resistance Thermometer NOs. 54,923/6, consisting of a pointer galvanometer and a slate slab with switching and regulating devices for one range from 300° to 700° C., with one lead, without lead mountings . '. . The minimum range can be selected for — 200° to + 100° or for — 100° to 0°, or for 0° to + 150°. for + 100° to + 300°, for + 200° to + 500°,tor + 300° to + 700°. It specially desired the indicating apparatus is supplied for still smaller ranges (say. .'ill to 4u") at an extra price. The range desired should be quoted when ordering. It is advisable to order at the same time the connecting leads (double stranded copper) lieiween the thermometers and the indicating apparatus, in order that their resistance can be taken into account in calibrating. See No. 54,940. 54.929. - - idem, Figs. A and B, for 6 connections with the same range For a larger number of connections and for connections having a different range, prices are quote!! on application. 54.930. Signalling Device for maximum and minimum distance recording; leads unmounted 54.931. Portable Indicator with one range, not smaller than in the case of No. 54.92S . . 51.932. -- idem, with two ranges, not smaller than in No. 54,928 54.933. Recording Galvanometer 54.934. Adaptor for eonneeting a number of thermometers with the measuring arrangement, up to ti connections "•1.935. -- idem, witli compensating resistances for the Thermometer leads t g. d. 9. 0.0 54.936. Accumulator, 13 ampere-hour capacity; can be used for about five days \vith one charge when worked continuously 54.937. 2 Accumulators in transport case 10. Id. D Price mi appli- cation 11. O.tl 12. 0.0 Price mi appli- raliun 1. 2.0 1. it;, o 0. s. d 1. l.u fl. 654l.(;:, i:;. :.! i No. 54 949. Pyrometers. 587 54 945. 1 = 5. 54 943. 1 : 4. 54948. 1:8. 54 949. 1 : 8. :>!.!»;>«. Compensator for connecting the Measuring Arrangement to a 110 volt D. C. Power Supply, Figure 54.939. - - idem, for 220 volts D. C 54.940. Double Strand, the resistance of which is taken into account during the adjustment. In lengths to 30 m £ 0. 1. 6 to 54.941. Optical Pyrometer after Wanner (Photometer), Figure, for measuring tempe- ratures from 840° to 2000° C., with regulating resistance, adjusting device and battery of accumulators 54.942. - - idem, with direct reading for temperature 54.943. Optical Pyrometer after Wanner (Photometer), for temperatures from 900° C. to 4000° C. 54.944. - - idem, with direct temperature reading, Figure 54.945. Pyrometer after Wedgwood, Figure, for Determining high Temperatures in accordance with the concretion of clay cylinders exposed to the heat, with 12 plate cylinders (Fr. phys. Techn. I., 2, Fig. 3054) 54.946. Clay Cylinders for above Per dozen , 54.947. Seger Cones, one set (20) 590°— 1850° C 54.948. Water Pyrometer after Siemens, Figure, for temperatures to 1,000° C. with thermo- meter and six copper cylinders each of 137 grammes weight . One of the copper cylinders is inserted into the furnace space, the temperature of which it is desired to measure, until such time as it has taken up the temperature of the same. It is then placed in the water of the calorimeter after the pointer of the sliding scale has been set to the tem- perature of the water, and during heating the maximum position of the mercury on the thermometer and on the sliding scale is read off. The sum of these two readings is the temperature which the iron body has attained in the furnace. 54.949. Water Pyrometer after Fischer, Figure, copper vessel with wood jacket, iron case, protecting screen, stirrer, with three similar cylinders of pure nickel, without thermo- meters (Fr. phys. Techn., 7th Edn., I, 2, Fig. 3081) Cl. 6541, 1744, 6125, 612C. £ S. d. 1.16.0 2. 2.0 1. 2.0 25. 0.0 27. 0.0 31.10.0 34. 5.0 1. 5.0 0. 3.0 0. 4.0 5. 0.0 2. 0.0 588 Thermoscopy. NIL ,04950 — 54 951. 1 : 9. 54952. 1:7. 54 953. 1 : 8. 54 954. 1 : 6. Thermoscopes after Galilei and Drebbel: see Xos. 54,792 and 54,793. 54,950. Thermoscope after Weinhold, Figure (W. D. Fig. 368 [348]), very sensitive in- strument for radiation experiments 54,951. Aneroid Thermoscope, sensitive apparatus . . Figure (Ztschr. f. d. phys. u. chem. U. 3, p. 141), very £ s. d. 0. 3.0 2.10.0 54,952. Leslie's Differential Thermometer, Figure, with detachable ground-on bulbs for automatic filling (M. T., p. 142), with a blackened bulb; also for use for measuring the intensity of radiant heat (M. P. Ill, Fig. 82 [II, 2, Fig. 81]) 0. 10. 0 54,953. Dilatation Thermometer after Rumford, Figure (M. P. Ill, Fig. 83 [II, 2, Fig. 82]), with short liquid threads, with detachable bulbs and glass stopcocks o. Ki.o 54,953 a. - - i d e m, after Friedr. C. G. Miiller, with connecting tube and cock for equalising pressure (M. T., Fig. 100) 0. If., o 54,954. Differential Thermoscope, Figure, with detachable ground-on glass bulbs, a glass bulb with wire spiral and terminals, Figure, for experiments on the thermal effects of the electric current; and two glass bulbs, each with one bismuth-antimony rod and terminals, Figure, for proving the Peltier effect 1.15.0 For shewing the thermal effect tln> l>ull> with wire spiral is placed on one end of the tlienno- scope, the. other being left open, and a supply of 2 — 4 volts together with a regulating resistance is connected In the terminals. For showing the 'Peltier effect the two bulbs with the I>ismu1h-antimon\ rod are placed on the t hennnscopc. the poles of the same name, e. g.. the nicUelled terminals of the bismuth, which are connected up by a lead and two accumulators in series, loget her wit h a regulating resi Matice and a pole commutator, being connected up to the free end. In one gl;:s> luilli heat in;: takes place when the current direction is from bismuth to antimony, a cooling effect taking place in the other. By 7-cvcrsing the current the opposite effect ensues. The current density should be aUmt r> amps. Too high a current generates too much heat in the rod and should be avoided. CI. I/IS. 6123, f.'l. :C53. No. 54957. Thermoscopy. 589 54 955. 1 : 6. 54957. 1:14. 54,955. Double Thermoscope after Looser, Figure, for a large number of experiments £ s. d. on heat, electricity, etc. (W. D. Fig. 32? [309]; Ztschr. f. d. phys. u. chem. U. 8, p. 291; 9, p. 265; 11, p. 105; 15, p. 257; 19, p. 333 ; Looser, Versuche aus der Warme- lehre und verwandten Gebieten) - ; 2.10.0 The apparatus consists of two manometers filled with coloured liquid, the long limbs of which are carried upwards quite parallely. A scale graduated in half centimeters admits of easy reading for the students; the lecturer himself can observe the height of the liquid on a second scale at the back. The shorter limbs of the manometer are cut off by wider vessels each having a cock and an attachment for rubber tubing. By means of the rubber tubing the sensitive air capsules (receivers) are connected with the manometers. The air capsules are constructed in suitable forms for the various experiments (see below). The following experiments can be carried out with the apparatus when use is made of the acces- sories pertaining thereto which should be selected from Nos. 54,956 — 54,972: D. Expansion of Bodies, Specific Heat and Atomic Heat, Thermal Conduction in Solids, Liquids and Gases, Radiant Heat, E. Heat and Work, F. Heat on change of state, G. Heat by Compression of Gases and Vapours, II. Heat during Chemical Reactions. I. Thermal Effects of the Electric Current. In addition the apparatus can be used as a Manometer. We supply with the apparatus two capsules with ccm graduation for liquids, two wide and four narrow glass beakers, one scourer, one bottle of filling liquid, two pieces rubber tubing. The accessories are set forth in accordance with definite series of experiments in such manner that under a List No. always all the objects necessary for the series of experiments are listed irrespective of whether they are mentioned again previously or subsequently. In subsequent orders it should be stated — paying due attention to what has been said above - whether such accessory parts are already available, in case it is not desired to duplicate them in the collection. The items marked \ are also contained in the "Small Collections ef Accessories" mentioned for the second time. The Figure Numbers in brackets appended to the accessories refer to the "Introduction" No. 54,956. 54.956. Introduction to above (Looser, Versuche aus der Warmelehre und verwandten Ge- bictcn, mit Benutzung des Doppel-Thermoskops), 3th Edn., 148 pages 0. 4. 6 54.957. Accessories for Experiments on Thermal Expansion, Figure (Experiments Nos. 1 — 9) 3. 4. 0 For experiments on the dilatation of vessels and rods, the floating of heated liquids on colder <>nrs. the irregular dilatation of water, change of volume and convection. 1 Boiling Flask, 1 litre, with tripod, cork, and connecting tube (Fig. 2). 1 porous Pot with tube connection (Fig. 46). 1 Sheet Iron Box with corrugated lid, with stand, test bars of brass and glass (Fig. 3). 1 indicating Device. 1 Gauge Glass. 2 Capsules weighted with shot (Figs. 4 and 31). 1 Standing Vessel of Zinc with 5 openings and 2 spherical air capsules (Fig. 5 and p. 14). 2 large Hemispheres of glass with bent tube (Fig. 6). 2 Pasteboard Cylinders with stand and beaker (Fig. 7). 2 large Hemispheres (glass) with straight tube (Fig. 7). 1 Rod with ring (p. 16). 54.95, a. Small Collection of Accessories for Experiments on Thermal Expansion (for Experiments Nos. 1, 2, 3, 4 and 6), consist ins solely of the accessories marked j in No. 54,957 0. 8. 0 Cl. 1754, (U89. 590 Thermoscopy. No. 54 958 — 54 959. 1 : 9. 54962. 1:10. 54,958. Accessories for Experiments on Specific Heats, Figure (Experiments Nos. 10 — 14) ....... 0. IL;. n For shewing the different specific heats of metals and liquids, for determining the ratio of specific heats with unchanged pressure and volume, and for confirming Dulong and Petit's Law on Atomic 1 1 cat. 2 Copper Pieces and 1 Lead Piece of the same weight and area. 1 Lead Piece three times as heavy. 1 Pressure Flask (Fig. 9). 54,959. Accessories for Experiments on Thermal Conduction, Figure (Experiments Nos. 15 — 26) .... For demonstrating the different thermal conduction of metals, the influence of the direction of grain in wood, the axial direction in crystals, bad conductors, the influence of specific heat on thermal conduction, the so-called cold conduction, thermal insulators, thermal conduction of different liquids and gases, the decrease of thermal conduction with decreasing gas-density. I!. II f3 rectangular bent Rods, two of copper and one of iron (Fig. 10). 2 Rods twice bent, of copper and lead. 1 Glass Capsule with lead rod. 1 Glass Capsule with copper rod. f2 small ground Glass Hemispheres (Fig. 11), with cork and board. f 2 Wood Slabs, one cut parallel and the other per- pendicular to the grain. f2 Zinc Beakers (Fig. 11). Slabs of iron, silk, cotton, copper, lead and marble. 2 Capsules weighted with shot, f 2 Vessels with cylindrical capsules and with si uppers (Fig. 13). 2 Vessels for liquids, 2 small hemispheres, 2 sheet iron holders (Fig. 14). 2 Vessels with cylindrical capsules. 2 jjla^s tubes and pierced rubber bungs (Fig. 15). 54,959a. Small Collection of Accessories for Experiments on Thermal Conduction (Experiments 15. l , and L';!). consisting solely of the accessories marked t in No. 54,959, for demonstrating thermal conduction in metal rods, wood slabs and liquids 0. 12. (» 54,960. 2 Crystal Plates cut parallel and perpendicular to axis (Experiment No. 19) 1. 4. 0 Cl. 6191, 6186, 6189. Xo. 54 964. Looser Thermoscope. 591 54 963. 1:12. 54 964. 1 : 9. 54,962. Accessories lor] Experiments on Radiant Heat (Experiments Nos. 27 to 53), without concave mirror, £ s. d. Figure 9. 0. O For demonstrating the unequal absorption of luminous and dark rays through rock salt and glass, total thermal reflection, thermal absorption of different materials and surfaces (also when thermal sources are unequal), thermal emission of various surfaces, thermal reflection, dependence of radiation on the incident angle. 2 Teclu Burners (Fig. 15 b). 2 Attachments with slotted burner for luminous flames (Fig. 15 b). 2 Attachments for non-luminous flames (Fig. 15 b). f 2 large Glass Hemispheres (lamp-blacked) (also Fig. 22) 2 four-sided prismatic reflectors, nickelled (Figs. 15 b and 20). f 4 thick and 4 thin Glass Plates. . 2 Rock Salt Slabs. 1 Rock Salt Cube. 2 small ground Hemispheres. 2 Mica Discs and 1 Gypsum Slab for heat-absorption. 2 ground Glass Discs. 2 Glass Troughs for water and solution of iodine in carbon-disulphide respectively. _' Stages for the reflectors with wire stands and holders for the glass troughs, on stands (Fig. 15 b). 2 cylindrical Sheet Iron Capsules for steam heating, with a bare and a sooted surface (cf. Fig. 191 and 4). Boiling Flask with T-tube and 2 lengths rubber tubing. 2 Capsules with glass attachments (Figs. 192 and 193). f 1 Leslie Cube. 1 four-sided prismatic Reflector sooted inside (Fig. 15 b). f 2 Stands with rings. 1 bare and 1 sooted Metal Vessel. 2 Capsules weighted with shot. 1 bare and 1 sooted Beaker with thermometers. f 1 Screen (Fig. 21). fl white metal Reflector (Fig. 21). f 2 Holders for 4 candles each, with 8 candles. 1 Card with circular hole (Fig. 22). 1 Gas Burner or Candle Holder with pivotted arm, on stand (Fig. 22). 1 Tube for thermal absorption (Fig. 23). Concave Mirrors for Experiments No. 51, p. 48: see Nos. 55,328 — 55,336. 54,962. a Small Collection of Accessories for Experiments on Radiant Heat (Experiments Nos. 45, 45b, 46, 48, 49), consisting solely of accessories marked t in No. 54,962, for demonstrating thermal absorption, thermal emission of different surfaces, a luminous and a non-luminous flame, thermal reflection, de- crease of thermal radiation with distance . 1 double Capsule, open (Fig. 24). 1 pressure flask (Fig. 25). 1 suction flask. Sheet Metal Box with corrugated lid, stand and indicating device, brass rod and glass tube.1) 1. 12. O 2. 6. O 54.963. Accessories for Experiments on Heat and Work, Figure (Experiments Nos. 54 — 64 and 67) .. The following can be demonstrated : generation of heat by friction, striking or bending, by shaking mercury and outflowing air; the freeing of heat by condensation, thermal consumption on rarifying gases. f 1 Small ground Hemisphere with cork and board. f 1 Board with emery cloth pasted on. f 1 Wood Block. •f 1 Wire with a piece of raw tin. fl Lead Slab. 1 Capsule with mercury (Fig. 24), with long handle. Friction Apparatus for the Whirling Table: see No. 52,048. Bellows for Experiments Nos. 17, 67 and 77: see No. 53,088. 1) If No. 54,957 is already available, the price is decreased by the following amount owing to the omission of metal box with corrugated lid, stand and indicating device 0. 18. 0' 54,963 a. Small Collection of Accessories for Experiments on Heat and Work (Experiments Nos. 54, 55 and 59), consisting solely of the accessories marked | in No. 54,963, for demonstrating heat produced by friction, striking and bending 0. 4. 0» 54.964. Accessory Apparatus, Figure, for shewing that the cooling of a gas when the pressure is reduced is proportional to the difference between initial and terminal pressure (Experiments Nos. 65 and 66) 1. 10. 0- 2 large Compression Flasks, 4 litres capacity, with connecting tubes; one with cork (Fig. 26), the other with cylindrical capsule, screw stopper and air-pressure manometer (p. 61). 1 Compression Flask, 8 litres capacity, with con- necting tubes and cork. Cl. 6180, 6187. 592 Thermoscopy. No. .4965 — 54 965. 1 : 12. 54966. 1:13. 54 967. 1 : 8. 54,965. Accessories for Experiments on Change of State (Experiments NOs. 68 — ill). Fig. 54.965. The following can be demonstrated; different thermal consumptions on melting and dissolving: the action of the August psychrometer; the heat on increasing the disgregation (formation of i): crystallising heat; cooling by evaporation; the degree of evaporation; velocity of evaporation; formation of ice on evaporation; formation of heat on freezing; cooling on evaporation in porous vessels: different heat of evaporation; constancy of the boiling point and melting point; raising and lowering of Mime by salts; the fact that the temperature of the water vapour formed from boiling salt solutions has the temperature of the solution; lowering the boiling point with decreasing pressure and raising it with increasing; the air thrown off from a rotating top. f 2 double Capsules (Fig. 28), one with wax, one with cetin. f 2 large Glass Hemispheres with straight tube. 2 spherical Capsules (Fig. 28 a), one covered witli muslin. 1 Device for evaporating ether by means of illu- minating gas (Fig. 29). 1 Cryophoms. 1 Porous Pot. 2 Impulse Hammers (Fig. 30). 2 Capsules with shot. 1 Boiling Flask with capsule, syphon tube and closed tube (Fig. 32). 1 short and 1 long syphon tube. 1 Gas Conduit, 1'ipe (Fig. 33). 1 large Hemisphere with straight tube, with i-ork .mil board. 1 beaker (Fig. .35). I <.l;i— , VCSM-|> fur Milphnrie acid and water respectively ( Fi>;. :ia. 71, 72, 73, 74, 75, 77), consisting solely of the items marked f under No. 54.1Mi5. for demonstrating the consumption of heat on melting, dissolving and evaporating, and of the heat on increasing the dis- gregation (formation of ions), of the influence of the degree of saturation, and of the formation of ice by evaporation o. Id. n Tops for Experiment No. 91, p. 78: see No. 52.O78/83, p. 291. 5».;iiiii. Accessories for Heat Experiments on Condensation of Gases and Vapours (Experiment N<» 92--!i9) n. K; \\ For demonstrating the heat during tin- absorptions of gases through solids and liquids, the con- densing of gases and water vapour on wearing apparel. 1 Boiling Flask with cork and glass tube. 1 loin sided Class Plate. :! cylindrical Capsules, two covered with wool, one with cotton, with plugs and boanl> 01 B194, 618:!, filSl. Xo. 54 968. Looser Thermoscope. 593 Pi 54 968. 1 : 9. 54,967. Accessories for Experiments on Heat from chemical combinations, Figure (Experiments Nos. 100 to 115) s. d. 10. 0 f 1 large Hemisphere with straight tube. 1 spherically widened Vessel (Pig. 47). f 1 large Beaker. 1 cylindrical Glass with lid (Fig. 38). 1 Receiver with capsule and cover (Fig. 38). 1 Apparatus for combining ammoniacal gas with It carbonic acid, with rubber bellows (Fig. 39). 2 rectangular bent Copper Rods. 2 Bunsen Burners No. 51,184. 54,9&7a. Small Collection of Accessories for Experiments on Heat from chemical Combinations (Experiments Nos. 100, 100 a, 101, 102 — 105, 107, 108, 109, 114), consisting solely of the apparatus marked f 'n No. 54,967 I 0. 3. 0 54,968. Accessories for Experiments on Thermal Effects of the Electric Current, F i i to 136 ;ure (Experiments Nos. 110 'rice (subject to fluctuation) For showing that heating is proportional to the length of the conductor, that it is proportional to the square of the current density, that it is independent of the specific resistance and thickness of conductor, demonstration and propagation of electric current lines, heat on decomposition of water, heat during electrical work, heating of wires by a discharge impulse, heat of the induction current, heating in a Hittorf Tube and in a thermocouple, formation of ozone by electric sparks. f2 platinum wire Spirals 15 and 30 cm long resp., 0.2 mm thick. f2 parrs adjustable Copper Electrodes (Fig. 40). 2 further platinum wire Spirals 15 cm long, with plugs, 0.2 mm thick. 2 platinum wires in glass bulbs, single and double wire-lengths. 1 Silver Wire and 1 Copper Wire 15 cm long, with plugs. 1 platinum Wire of double thickness, 15 cm long, 0.4 mm diameter with plugs. 2 small Boards with tinfoil slabs, 2 connecting blocks, and some sheets tinfoil. 2 small Hemispheres. 2 pair platinum Electrodes. 1 Stopper with accumulator plates, size of 3,5 x9 cm. 1 large Capsule for above. 2 platinum Wires of 2.5 and 1.5 ohm respectively. 1 pair Copper Electrodes. 2 small zinc-carbon Electrodes. 1 small electric Motor. 1 rubber Bung with manometer and 3-way cock, also with 2 platinum electrodes 1 sq. cm. 1 large Capsule for. above. f 1 Riess Bulb with tube attachment. 2 Glass Bulbs with thermocouples. 1 rubber Bung with thick copper wires and eye for potassium iodide starch-paste paper, after Liidke (Fig. 45). 1 Wood Box for containing preceding parts, see Fig. 54,968. Batteries of Accumulators with pachytrope for connecting the cells singly and in parallel: see Nos. 60,946/93. Influence Machines, Leyden Jar Batteries, Measuring Flasks, spark-drawing Devices, Induction Coils, Hittorf Tube: see "Electricity" Section. 54,968a. Small Collection of Accessories for Experiments on Thermal Effects of the Electric Current (Experiment* Nos. 116, 117, 118,1 119, 120, 121), comprising solely the items marked f in No. 54,968 Cl. 6199. 8. 5. 0 0. 16. 0 38 594 Thermoscopy. No. 54 969 — 54 969. 1 : 9. 54 969 A. 1:8. 54 970. 1 : 8. 54,969. Accessories for using the Thermoscope as a Manometer (Experiments Nos. 137 — 157a), Fig. 54,969 and 54.969A For experiments on gas osmose, the absorption and ejection of gases, relations between carbonic acid and lime water (formation of stalactites), demonstration of water content and of carbon dioxide in air, vapour tension of water, alcohol and ether; buoyancy of gases, propagation of pressure, suction effect of outflowing air, measurement of adhesion in capillary tubes, pressure of a liquid column, demonstration of tension in soap bubbles, Newton's colour rings, porosity of clay. £. s. (1. 1. 16. 0 1 Porous Pot. 1 Glass Beaker for above. f 2 Osmose Apparatus after Niemoller (Fig. 46 a). •j-2 Vessels for inserting. 1 1 Bell Funnel after Steinbrinck. f2 spherical Capsules with constriction (Fig. 47). 1 forked Tube (Figs. 48 and 52). 1 multiple bent Glass Tube on stand (Fig. 54.969A) (Fig. 48). 1 Model of water air pump (Fig. 49). 1 Vaporiser (Fig. 50). 1 Tube for suction and pressure effects (Fig. 51). 3 different Capillary Tubes. 1 wide Glass Tube with point. 1 soap-bubble Apparatus (Fig. 53). 1 Clay Slab with funnels attached 54.969 a. Small Collection of Accessories for using the Thermoscope as a Manometer (Experiments Nos. 137a, 137 b, 138 — 149, 157), comprising solely the items marked fin No. 54, 969, for experiments on gas osmose, alisorption and ejection, tension in soap-bubbles 11. 12. (i :>4.'.i7o. Accessories for various Experiments, Figure (Experiments Nos. 158 — 161) Demonstration of heat by physiological processes, proving that solutions of salts take up some times a smaller and sometimes a larger space than the individual substances together, inequality of ililatcitinn of two liquids. •2 Erlenmeyer Flasks with stoppers, spherical tubes and water bath. Apparatus for expansion of water on frcezinic (Fig. .-,.-,). •2 Capsules filled with shot. Cylindrical Vessel with tube attached. Stopper with glass rod and perforated reagent r.i.'.iTi. Accessory Apparatus for Determining the absolute Expansion of Water, Figure (Figs. 56—58) .".t .'.17:.'. Dew-point Finder after Looser, Figure (Experiment No. 163, Fig. 59) . Boxes and Stands for taking the various accessories are prepared on application and chained at lowest possible cost. \Ve would ask in this ease that the collections of accessories should he mentioned which are to he placed in boxes or on stands. . .v>09, 6197. •i. 10. 0 o. to. II No. 54 975. Kolbe Thermoscope. 595 54971. 1:11. 54 972. 1 : 6. 54975. 1:10. 54973,54975,54976. 1:10. 54,973. Differential and Double Thermoscope after Kolbe, Figure, for experiments on heat and electricity (Ztschr. f. d. phys. u. chem. U. 15, 1902, p. 333; Kolbe, ,,Anleitung zu 30 der wichtigsten Schulversuche", see No. 54,974). For making the experiments a suitable selection should be ordered with the apparatus from Nos. 54,975 — 54,997 . In some of the collections of accessories, e. g., in No. 54,995, a few necessary apparatus for the experiments are mentioned at the end, these not being included in the price. These articles must be specially ordered unless already available. The Figure Numbers mentioned in the Accessories refer to the Introduction Number 54,974. The apparatus consists of a polished wood stand to the back wall of which are fixed two mano- meters having plain scale. The two limbs of the manometers are provided with enlargements and have e?ch at their upper end a stopcock and a funnel-shaped opening for filling. The enlargements have tube attachments HO as to be capable of being connected to receivers by lengths of rubber tubing. The receivers are attached to sliders which can be slipped along a bar, provided with a scale and fixed above the stand. Supplied with the apparatus are: 9 sliders, four with long tubes for the receivers, three with medium long tubes for the double screens, two with short tubes for the thermal sources; 1 attachable tube for the sources of heat (box shape); 4 lengths rubber tubing, each 400 mm long; 1 filler (Fig. 2); 1 piece cardboard for concealing the second scale; 1 small funnel for flushing the manometer tubes; 1 small flask with 100 ccm of aqueous solution of ocetine blue (ready for use); 1 double screen without piece cut out. .">4.974. Introduction to 30 of the most important School Experiments with the Kolbe Diffe- rential and Double Thermoscope (48 pages, 34 illustrations) (in German). Gratis and post-free. The Figure Numbers mentioned in the following lists of accessories refer to this Introduction. 54,975. General Accessories for Experiments on Heat, F i g. 54,973 (Fig. 1, Experiments Nus. 1—16) (a) 1 Boiling Flask with rubber bung; 1 Tube with 2 stopcocks; 1 thick walled Rubber Tube 1 metal stand for the 50 cm high (£0.6. 0); 4i> cm long; 1 fork-shaped Glass Tube with 2 short lengths rubber tubing and 1 metal stand for the lioiling flask (£ 0. 11. 0); (b) 1 small Stand with spirit lamp and wire gauze globe I (c) 1 (How Lamp with socket, on plate with two terminals (£ 0.9.6). £ s. d. 4. 8. 0 1. 6. 0 Cl. 6190, 6195, 6103, .6179. 33* 596 Thermoscopy. No. 54 976 — 54976,54977. 1:10. 54983. 1:16. 54 984. 1 : 10. 54 985. 1 : 7. 54.976. Accessories for Experiments on Absorption, Emission and Permeability of Heat Rays, Figure (Experiments Nos. 1 — 4) (a) Thermal Sources: 4 Metal Boxes for steam heating, black-black, black-white, black-polished, polished-dull (Figs. 3 and 4, £ 1.2.0); (b) Receivers: 5 Metal Receivers, round pattern, 2 black-white, 1 each black-polished, white-dull, polished-dull (Figs. 3 and 4, £ 1. 7. 0); (c) 2 double Screens with rect- angular piece cut away for taking rock salt, plate glass, etc. slabs (Fig. 4, £ 0. 6. 0); (d) 2 U-shaped Alu- minium Sheets for closing the apertures (£ 0. 2. 0); (e) 2 Slabs mounted in cork, 40 x30 mm. of rock salt and plate glass (Fig. 4, £ 0. 13. 0); (f) 2 double Screens with round opening 75 mm diameter for taking the flat glass vassels (Fig. 5a, £ 0.7. 0); (g) 4 flat thin-walled Glass Vessels for distilled water, alcohol, iodine solution and concentrated ferrous sulphate solution (Fig. 5b, £ 0. 13. 0). The accessories No. 54,975 should also be ordered and possibly also Nos. 54,978 — 54,982. 54.977. Board with 15 Brass Sockets for containing the Metal Eeceivers, with pasteboard cover, see Fig. 54,976 '. 54.978. Alum Slab, mounted in cork, (addition to Expt. No. 3) ,. 54.979. Gypsum Slab ditto ( ditto 3) 54,980. Mica Slab ditto ditto 3) £ s. d. 4.10.0 54.981. Rock Crystal Slab, cut perpendicular to axis, mounted in cork (addition to Expt. No. 3) 54.982. Rock Crystal Slab, cut parallel to axis, mounted in cork (addition to Expt. No. 3) 54.983. Accessories for Experiments on Reflection of Thermal Rays on concave Mirrors, double and triple reflection, cold rays (Experiment No. 5, I — III), Figure (a) 2 spherical concave Mirrors, 400 mm diameter and 175 mm focal distance, of German Silver. on adjustable stands (Figs. 6 and 31, £ 6. 0. 0); (b) 1 small Metal Receiver 65 mm diameter on adjustable stand, and 1 rubber tube 55 cm long, and 1 small Glass Tube (Figs. 6 and 31, £ 0. 13. 0): (c) 1 adjustable Stand for the spirit lamp stage, with wire gauze globe (Figs. 6 and 31, £ 0.6. 0); (d) 1 White-metal Slab, 600 and 400 mm (Fig. 7, £ 0.1.0); Accessories No. 54,975 should also be ordered. 54.984. Accessories for Experiments on Refraction of Thermal Rays (Experiment No. 6, Fig. 8), Figure . . (a) 1 semi-cylindrical Double Screen with adjustable gap (£ 1.0.0); (b) 1 equilateral Rock Salt Prism, 35 mm side and 70 mm height, with stage (£ 3.17.0); (C) 1 rotary Bar with divided circle (£ 1.8.0); (d) 1 simple plane Gap (£ 0.12.0); (e) 1 semi-cylindrical Receiver, the plane side black (£ 0. 9. 0); (f) 1 Wire Gauze Globe 70 mm high, on thick wire stirrup (£ 0. 2. 0). Accessories No. 54,975 should also be ordered. 54.985. Accessories for Experiments on Total Reflection and Reflection on plane Metal Mirrors (Experiments Nos. 7 and 8, Fig. 8), Figure (a) 1 rectangular Rock Salt Prism, 35 mm side and 70 mm height, with stage (£ 3. 17. 0); (b) 1 nickelled plane Mirror, o. metal, 100 x 100 mm (£ 0.4.0). Accessories Nos. 54,975 and 54,984 should also lie ordered. 54.986. Accessories for Experiments on Thermal Conduction of Solids (Experiments No. 9, Fig. 9), Figure (a) 2 Metal Receivers in the form of truncated cones (£ 0. 11. 0): (b) 2 Sheet Iron Flasks for hot water or steam heating (£ 0. 9. 0); (C) 2 each round Wood Slabs cut with and across the Limin. ><( pine, poplar and oak, 50 mm diameter, 10 nun thick (£ 0. 2. 0). Accessories No. 54,1)75 should also be ordered and perhaps also Nos. 54,987/90. | « fl.6166, 6164, 0188, 617.'.. 1.12.0 0. 11. 0 I). 11. II 0. 11. 0 0. 14. o 0. 14. It 7. 0. 0 7. 8. 0 4. 1. 0 1. -2. u Xo. 54995. Kolbe Thermoscope. 597 r 54992. 1 : 10. 54 991. 1 : 7. 54 994. 1 : 6. 54 993. 1 : 7. 54 995. 1 : 7. 54.987. Gypsum Slab, round, 50 mm diameter, 10 mm thick (addition to Expt. No. 9) 54.988. Alum Slab, round, 50 mm diameter, 10 mm thick (addition to Expt. No. 9) 54.989. Rock Crystal Slab, round, 50 mm diameter, 10 mm thick, cut parallel to axis (addition to Expt. No. 9) 54.990. Rock Crystal Slab, round, 50 mm diameter, 10 mm thick, cut perpendicular to axis (addition to Ex- periment No. 9) 54.991. Accessories for Experiments on Thermal Conduction of Metal Rods (Experiment No. 10, Fig. 10), Figure (a) 1 Sheet Metal Vessel with 3 necks (£ 0. 7. 0); (b) 2 Copper Rods, 250 mm long, 6 mm thick, in tubular glass receivers (£ 0. 6. 0); (c) 1 Lead Rod, 250 mm long, 6 mm thick, in tubular glass receiver (£ 0. 3. 0). The following rods are also intended for these experiments. 54.992. 6 further Metal Rods, Figure, 250 mm long, 6 mm thick, in tubular glass receivers (a) Aluminium (£ 0. 3. 0); (b) Brass (£ 0. 3. 0); (c) German Silver (£ 0. 3. 0); (d) Zinc (£ 0. 3. 0); (e) Tin (£ 0. 3. 0); (f) Iron (£ 0. 3. 0). 54.993. Accessories for Experiments on Thermal Conduction of Liquids and Gases (Experiment No. 11), Figure without box (a) 4 Double Vessels of glass, for water, alcohol, oil and mercury; 1 length Rubber Tubing with glass tube. (£ 0. 18. 0); (b) 1 Wood Fillet with hinge, for taking two double vessels (£ 0. 3. 0); (c) 5 Glass Double Vessels, filled with air, oxygen, hydrogen, illuminating gas, and carbon dioxide, sealed up (£ 1.8.0): (d) 1 evacuated Double Vessel, unsilvered (£ 0.5.0); (e) 1 evacuated Double Vessel silvered inside (£ 0. 8. 0). 54.994. Accessories for Experiments on Sp33lfic H?at 0? Solids and Liquids (Experiments Nos. 12 and 13) Figure (a) 2 Double-walled Glass Receivers with com graduation and wood lids (Fig. 12. £ 0. 9. 0) : (b) 5 Metal Bodies of same weight ii-id sa'iic area. 2 of copper, 1 eaoh of lead, tin and iron (£ 0. 9. 0). In addition, the sheet iron vessel No. 54, 991 a must be available. ."i4.ii!)."). Accessories for Experiments on Thermal Consumption on Evaporating, Generation of Heat by Mechanical Work, Decrease of Heating with the Square of the Distance (Experiment No. 14 — 16), Figure . (a) 2 thick artificial Corks, f>0 mm diameter, 12 round blotting paper discs, 50 mm diameter and 1 piece sandpaper (£ 0.2.0); (b) 1 Wire Gauze Globe, 30 mm high, on wire stirrup (£ 0.2.0). In addition, the two Receivers Xo. 54.9S(i a and the two Rer.eivo.rs No. 54,976 b, black-white, must be : "ailable. Cl. 6160, 6170, 6165, 61B2, 6172 8159. £ S. d. 0. 10. 0 0. 10. 0 0. 13. 0 0. 13. 0 0. 16. 0 0. 18. 0 3. 2. 0 0. 18. 0 0. 4. 0 598 Thermoscopy. N... :,4996 — 54 996. > : 7. 54 997. 1 : 7. 54998. 1:10. 54,996. Accessories for Experiments on the Heating Effect of the electric Current (Experiments Nos. 17 — 23), Figure (a) 1 tubular Receiver with a constantan wire 100 mm long (Fig. 13, £ 0.4.0); (b) 2 tubular Receivers each with constantan wire 200 mm long (Figs. 13 and 15, £ 0.9.0); (c) 1 Series Resistance with a constantan wire 200 mm long (Fig. 15, £ 0.4.0); (d) 1 Closed Circuit Fall Trough No. 51,729 (Fig. 14, £ 1.6.0); (e) 2 Constantan Wire Spirals with cork mount, contained in reagent glasses (Fig. 16, £0.5.0); (f) 2 tubular Receivers each with 2 constantan wires (£0. 9. 0); (g) 1 tubular Recei\ IT with three wires of copper, iron, and constantan (Fig. 18, £ 0.5.0); (h) 1 tubular Receiver with three wires of different diameter (Fig. 19, £ 0.5.0); (i) 1 Lamp Resistance with three 110 volt Glow lamps (£ 0.16.0); (j) Double Conductor 2 m long with screw plug and plug contact and simple connecting lead 40 cm long (£ 0. 5. 0); (k) 2 pair Copper and Zinc Rods in cork mount (Fig. 20, £ 0. 4. 0); (1) 2 tu- bular Receivers with double rods of antimony and bismuth (Fig. 21, £ 0.18.0). If the network voltage is other than 110 volts kindly quote pie-sure when ordering, double-walled Receivers No. 54,994 a are also used. The two 54,997. Accessories for Experiments on Gas Osmose (Experiments Nos. 24 and 25), Figure 1 Porous Pot with rubber stopper and glass tube and a gla-s beaUer (Figs. 22 and 23). 54.99S. Accessories for Manometric Experiments, F i g u r e (Experiments Nos. 2*>. 27. 20. 3D). Action <>i l)ubrol'ski Aspirator. Itoflection of Sound Waves after Trussevitch- Rostov/eft'. Absorption of through a rotating body carries air with it (a) 1 Vaporiser as aspirator (Fig. 24, £ 0.2.0); (b) 1 Kiunlt Manometer in a Trusscvitcli Mop- cock arrangement, No. 53,1!U, with sound horn and with pointer for direction of air current, on stand (Figs. 25 and 32, ' £ 1.0.0); (c) 1 tuned Pipe on Maud (Fius. :>.-, and 32. £ 0.12.0): (d) 1 Absorption Vessel, consisting of two tall cylinders, one spring wire net and one irhiss plate (£ 0.10.0); (e) I pair Wire Net Tongs (Fig. 34, £ 0.4.0); (f) 1 Pasteboard Cylinder with bottom, for fixing on the \Vbirlinir Table (£ 0.2.0). In addition, spherical concave Mirror No. 54,983 a is used for I-', xperimenl No. L'7 and one black-polished l!ecei\er No. 54.976)) for Experiment. No. 30. Boxes and Stands for Inking the in.( HI:;. 6 Tube Receivers with Metal Wires for electric Resistance Comparisons, Figure, with wood fillet for placing on the sextuple manometer ' 1. 4. 0 The wires included in the Receivers are of equal length and thieknr— . These Receivers can also be inserted in the heating boxes contained in No. 55,000. A closed -circuit fall trough No. 54,996 d is necessary for the experiment and should be ordered with the above if not already available. 00,00.4. - idem, without the receiver with platinum wire 1. 0. 0 55,005. 6 Double Glass Vessels for Comparison of electrical Resistance (Kolbe -Skellon, Introduction to electricity, part 2, Fig. 128), divided in cubic centimetres, and 6 Wires conducted through Corks, with wood fillet for placing on the sextuple manometer, for the Lenz-Looser experiment, Figure ... 2. 0. 0 55.008. Box for storing the glass parts of Xos. 55,000 — 55,005 0. 15. 0 •5,009. — idem, the removable lid being provided with 15 sockets j 2. 0. 0 Cl. 1764, 6169, 1763, 3414. 6161. 600 Thermoscopy. Heat and Change of State. No. 55010 — 55 013. 1 : 4. 55016. 1:3. 55019. 1:12, 55.010. Colour Thermoscope after H. Eebenstorff, Figs. A — D (Ztschr. f. d. phys. u. chem. i £ s. d. U. 9, 1896, p. 227; and 15, 1902, p. 145; W. D., 4th Edn., pp. 568 et seq.) .... 1. 2. 0 The mode of action is based on the fact that mercuric iodide with which the apparatus in question is coated changes its colour when submitted to temperature variations. While it is quite yellow at ordinary temperature, it becomes red when heated to from 45° to 50° C., assuming the yellow colour when cooled below 35° C. The complete set of apparatus comprises: 1 Card with 5 thermopaints, 80 x 160 mm; Glass Tubes filled with hydrogen and air, Pig. C; 1 Tinfoil Screen, Fig. A; 1 Screen with rock salt and glass slab, Fig. D; 1 Sheet Iron Screen with two wood wedges, Fig. B; and 1 Brass Stand with polished wood base. 55.011. 10 thermoscopic coloured Sheets after Eebenstorff (Ztschr. f. d. phys. u. chem. U. 21, 1908, pp. 291 and 304) 0. 4. 0 55.012. Autogram Discs for colour thermoscopes, Figure 0. 3. 0 The disc is coated half yellow and half red (with silver mercury iodide and copper mercury iodide , respectively) and transparent sections cut away. When held high above a flame the temperatures of the enantiomorphic molecular changes (45° and 70° C.) are shewn. 55.013. Sensitive thermoscopic Sound, Figure 0. 10. 0 The Sound, coated with thermoscopic paint, consists of a sheet iron capsule for lukewarm water or thermophoric substance. Change of State. 55.014. Freezing Thermometer, for shewing the over-cooling of water and the generation of heat on freezing, with stand (M. P. Ill, Fig. 320 [II, 2, Fig. 88]; Gan.-Eein., Fig. 336) 0. H). u 55.015. — idem, Figure, with transparent scale for objective demonstration, small pattern, with stand 0. 7. 0 55,016. Hollow Iron Sphere with closing screw (Explosion Ball), Figure, for shewing the increase of volume when water freezes (W. D., Fig. 351 [331]; Gan.-Eein., Fig. 33H; M. T., p. 153) 0. 1. 8 The closing screw need only be provided once and can be used for a number of experiments. ! '<•>. ol 7. Iron Sphere alone, as spare 0. o. 10 55,018. Cooling Vessel of stout wood, for above, with lid, for holding the fractured pieces of the bursting sphere 0. 5. 0 Ice Machines for generating Ice by a freezing Mixture or by the combinal ion of Heat on dissolving Ammonium Nitrate: see p. 214. Ice Machines after Carre", Figure, with air pump (M. P. Ill, Fig. 360 [II, 2, Fig 217]; Gan.-Man., Fig. 172, I, II; Gan.-Eein., Fi. o 55.037. Apparatus after Weinhold, F i g u i e, for shewing the behaviour of Saturated and Superheated Steam (W. D., Fig. 357 [337]), height of apparatus 1.20 m 55.038. — idem, with iron stand (W. D., Fig. 357 [337] and p. 523 [485] — Bemavk) . •2. 0. 0 2. 10. 0 55.039. Apparatus after Dalton-Be"gnault, Figure, for Measuring the Tension of Steam below the Boiling Point (M. P. Ill, Fig. 249 [II, 2, Fig. 121); the steam vessel is placed, together with the barometer, in one bath. The difference between the mercury columns (reduced to 0°) gives the pressure 2. 10. 0 55.040. Apparatus after Dalton, Figure, for Measuring the Tension of Water Vapour between 0° and 100° C., with stand, burner, tripod, heating vessel, and thermometer (Gan.-Bein., Fig. 344) 3. lo. o 55.041. Apparatus for Measuring the Tension of Vapour from Salt Solutions, Figure (\V. I)., Fig. 358 [338]) 1. 0. o 5^.762. Barometer Tube with iron tripod stand, Fig. 52.762. p. 371, for shewing the difference between gases and vapours (M. P. Ill, Fig. 237 [II, 2, Fig. 1 0!>|), the, glass tube with graduation, with Tube Holder and Index 1. 16. 0 52,752. 3 Barometer Tubes in mercury bath, Pig. 52,752, p. 370, with stand (M. I'. III. l-'ig. 236 [II, 2, Fig. 108]), suitable for shewing the difference between gases and vapours . . 1.10. u 51,412. Filling Pipette, Fig. 51.112, p. 220, for tubes the lower' opening of which plunges in a liquid 0. 3. 0 * Can In- used witli the Projection Apparatus. U. 1783. 17S5, 178S No. 55047. LeidenJrost's Experiment. Dalton's Law. 603 55 041. 1 : 5. 55 042. 1 : 2. JJdw* 55040. 1:14. 55 043. I : 6. 55 044. 1 55047. 1 : 1C. 51', 753. 3 Barometer Tubes as No. 52,752, the tubes having etched graduation, with funnel- £ s- * [II, 2, Fig. 12!»|; Gan.-Man., Fig. 495; Gan.-Eein., Fig. 347), by observing the boiling point at diffe- rent pressures 16.0. (I . Apparatus after (lay-Lussae and Theiiard. Figure, for Determining the Tension Of Vapours mixed with Cases (dan. -Man., Fig. 4!»S; Gau.-Hein., Fig. 378) t. 0.0 CI. 1797. 41.17,3417, .••021', 50242, 341.".. No. 55061. Tension of Vapour. 605 55055. 1:11. 55 054. 1 : 20. 55 060. 1 : 6. 55057. 1:12. 55.057. Apparatus for Shewing the Equilibrium of Vapour Tensions in unequally heated com- municating Spaces, Fignte (M. P. Ill, Fig. 216 [II, 2, Fig. 133]), on stand . . . 55.058. Boiling Vessel for Shewing Ebullition at higher or lower Pressure than the atmospheric, with tall cylinder and angle tube (W. D., Fig. 354 [334]) 55.059. Apparatus for Delaying Ebullition by a Soap Solution, Figure (W. D., Fig. 359 [339]) 55.060. Apparatus for Retarding Ebullition with pure Water, Figure (W. D., Fig. 360 [340]), so-called Water-Hammer, for shewing the force with which the water is impelled when the "retardation of ebullition" disappears; with sheet iron tube for heating by steam 55,061. - - idem, without sheet iron tube £ s. d. 0.18.0 0. 6.0 0. 3.0 0. 4.0 0. 3. 0 Cl. 1794, 6200, 3418, 4810.3866. 606 Heat and Change of State. Xo. 55 062 — 55 063. 1 : 10. 55064. 1:10. 55 067. 1 : 5. •*— 3* 55 066. 1:5. 55 069. 1:6. 55 072, 55 074. 1 : 6. £ s. d. 55,062. Water Hammer (Fr. phys. Techn. I, 2, Fig. 2197 [I. Fig. 371]) 0. 2. 0 The water hammer is used, for example, in the following demonstrations: for Shewing Retar- dation of Ebullition; Retardation in Freezing (cooling down of water when freezing, M. T., p. 152), the lowest position of boiling point at low pressure (when warmed with the hand, M. T., p. 157), the Falling of a liquid in vacuo without splitting up. .">:>, 063. — idem, with constriction and point (Singing Water Hammer), Figure (Fr. phys. Techn. I, 2, Fig. 2919) 0. 2. 0 55.064. -- idem, after Donney, Figure o. 3. o 55.065. Pulse Hammer (Fr. phys. Techn. I, 2, Fig. 2916 [I, Fig. 373]), for shewing the boiling of ether in vacuo 0. 1. r> 55.066. Apparatus, F i g u r o, for Shewing that the Boiling Point of Salt Solutions is higher than of pure Water, with thermocouple (W. D., Fig. 356 [336]) 0. (i. o .").">. o»J7. Apparatus for Determining Boiling Point, Figaro, with thermometer (W. u. Iv. ]>hy,s. Prakt., Fig. 101), especially for water, ethyl and amyl alcohol 0. 1'2. u :>:>.06N. Apparatus for Ebullition under low Pressure at low Temperature (M. P. Ill, Fig. 256 [II, 2, Fig. 127]) 0. 6. 0 .V), <)(><>. Papin's Digester, of brass, on tripod, for ll/.t atmospheres, with safety valve and thermometer 2. 0. (I \V«> *\iM lie picked to hiivc the I'apin Digesters tested officially on receipt of tin- fees (£ 1.0.0 to £ 1. 5. 0) for lln- tests. ."»:>. 070. - - idem, with Spring Manometer 70 mm diameter 2. 8. 0 .">.">. 071. Papin's Digester, larger, Figu re, of stout brass, for 10 atmospheres, with safety valve and thermometer 3.16.0 i .">."». 072. - - idem, with Spring Manometer 70 mm diameter 4. .10. o Cl .Wli. 1M03, 1881, 1784, 4704. 180.'.. No. 55081. Ebullition, Solidification, Fusion. 607 55 080. 1 : 5. r 55079A 1 : 12. 55 079 B. 1:3. 55.073. Papin's Digester for 20 atmospheres, of stout copper with gunmetal top, with safety valve, thermometer and cock (M. P. Ill, Fig. 257). The thermometer is divided to 250° C. and plunges in an iron box which "should be filled with mercury . . . . . 55.074. - - idem, with Spring Manometer 100 mm diameter, Figure (M. T., p. 159). 55.075. Device after Faraday, for freezing mercury in a powerful flame by means of solid carbon-dioxide, Figure (W. D., Figs. 401 and 402 [381 and 382]; M. P. Ill, Fig. 304 [II, 2, Fig. 161]), consisting of cloth bag, stand, plate, small iron vessel on long stem and platinum wound wire triangle; but without platinum crucible and blast lamp . 55.076. Apparatus for Freezing Mercury by Evaporating Sulphurous Acid, Figure (W. D., Fig. 405 [385]), consisting of a flask with inset, a drying flask, and 6 condensing vessels 55,077. - - idem, without drying flask •V).078. - - idem, for producing temperatures to about — 101 ° C. by a mixture of solid carbon dioxide and ether (W. D., Fig. 406 [386]) 52,655. Inset for the Oersted Piezometer, for demonstrating the lowering of the melting point of water by pressure, after Thomson (M. P. Ill, Fig. 327 [II, 2, Fig. 95]; Gan.-Eein., Fig. 332) This apparatus consists of a lead slab, a sensitive ether thermometer in protecting tube and a manometer. 55.079. Melting Point Determination Apparatus, Figs. A and B, with stand and thermometer to 360° C. (W. u. E. phys. Prakt., Fig. 98) 55.080. Apparatus for Producing Ice by the Evaporation of Sulphuric Acid in Vacuo, Figure, after Leslie (M. P. Ill, Fig. 358 [II, 2, Fig. 215]), consisting of one small receiver, sul- phuric acid vessel, and cork dish on tripod, for the air pump .V>.osi. Thin-walled Dish of Sheet Copper with Wood Slab after Bb'ttger, for producing ice by evaporation of ether or carbon-disulphide (M. P. Ill, Fig. 362 [II, 2, Fig. 219]) £ s. d. 5. 4.0 6. 4.0 1. 4.0 0.15.0 0. 10. 0 0. 12. 0 2. 5.0 1. 0.0 0. 3.0 0. 1. 3 53,073. - - i d e m, for the air pump (W. V., Fig. 409), see Fig. 53,073, p. 405, without receiver ! 0. 3. 0 Cl. 4545, 1820, 1801, 1821, 1802. 608 Heat and Change of State. No. 55 083 — 55 087. 1 : 5. 55 089. 1 : r>. 55 088. 1 : 3. 55 090. 1 : 4. 53.074. Refrigerator after Carre1, Fig. 53,074, p. 405 (W. D., Fig. 391 [371]), for producing ice by evaporation, and with enclosed ether glass for demonstration of the heat freed by condensation of steam, on stand 53.075. - - idem, without ether glass, after Berberich (W. D., Fig. 390 [370]; Fr. phys. Techn. II, 2, Fig. 3631) 53.076. Refrigerator after Weinhold, Fig. 53,076, p. 405, completely assembled for setting on the plate of the air pump (W. D., Fig. 392 [372]) . 55.083. Apparatus for the Retardation of Freezing, after Weinhold (W. D., Fig. 350 [330]) 55.084. Cryophorous after Wollaston (M. P. Ill, Fig. 361 [II, 2, Fig. 218]) 55.085. Cryophorous after Weinhold (W. D., Fig. 393 [373]) 55.086. Cryophorous after Grimsehl, specially adapted for demonstrating ebullition at low temperature (Ztschr. f. d. phys. u. chem. U. 16, 1903, p. 376), with thermometer. . 55.087. Sulphuric Acid Cryophorous after Weinhold, Figure (W. D., Fig. 394 [374]), with funnel for filling 55.088. Apparatus for Evaporating Ice, F i g u r e (W. D., Fig. 395 [375]) 55.089. --idem, Figure, with platinum gauze for rendering incandescent by ;i voltaic current (W. D. Fig. 396 [376]) * 55, (i(»o. Andrews' Press for Compressing and Liquefying Carbonic Acid, F i g n r c, arranged for the Projection Lantern (W. D., Fig. 363 [343]) The carbonic acid tube is protected for transit by a screw-on metal sheath. The liquefaction of the carbon dioxide is plainly visible. If the apparatus is set up before the Projection Lantern (which can be done very conveniently), the carbonic acid tube is cooled by blowing air front above through a clean glass tube screwed on, see Pig. 55090. £ s. d. 0. 11/0 0. 9.0 0. 10. 0 0. 2.0 (i. 2.6 0. 3.0 0. 10. 0 0. 4.0 0. 10. 0 0.15.0 2. 4.0 * Can be used with the Projection Apparatus. Cl. 1808, 4890, 1814 No. 55097. Solidification. Liquefaction. 609 55 096. 1 : 6. £ s. d. 55.091. Carbonic Acid Generator, Figure (W. D., Fig. 398 [378]) 3. 6. 0 55.092. Steel Cylinder, 3 litres capacity, Figure, filled with 2 kg Carbonic Acid (W. D., Fig. 397 [377]), without tipping device 1.10.0 55.093. Filling No. 55,092 with 2 kg Carbonic Acid 0. 5. 0 55.094. Tipping Device for the Carbonic Acid Cylinder, Fig. 55,092, without steel cylinder, reducing valve, or capacity indicator 1. 16. 0 55, 094 a. Portable Stand for large Steel Cylinders 10 — 12 litres, Figure I 1. 10. 0 55. 005. Stamp, Plate, Mould and Frame for pressing carbonic acid plates, also polished Brass Ball 2 cm diameter (Krdmann, Anorganische Chemie, Figs. 187 — 190) 0. 8. 0 55.090. Apparatus for Demonstrating the Liquefaction of Gases, after Cailletet, Figure (M. P., Ill, Fig. 309 [II, 2, Fig. 166]), for a pressure of 300 atmospheres, with Steel , Pump and reservoir 32. 10. 0 •"'"'.097. - - i d e in, for a pressure of 1000 at 40. 0. 0 Cl. 4105, 1818, 6218, 1819. 39 610 Heat and Change of State. No. 55 098 - 55 098. 1 : 8. 55 103. 1 : 7,5. 55,098. Demonstration Apparatus for Generating Liquid 7 Air after Heylandt (Ztschr. £. d. phys. u. chem. U., 22, 1909, p. 360), Figure...* 55.099. Steel Cylinder containing Compressed Air for above 55.100. Auxiliary Apparatus for Generating Solid Air . . 55.101. Refrigeration Thermometer 55.102. Pressure Gauge for valve-regulation a s. 6.10. 2. u. 1.10. i. o. 1. 4. d. (I 55,103. Demonstration Apparatus for Generating Liquid Air after Olszevski, Figure (Drudes Annalen der Physik, 10, 1903, p. 776) 31. n.(t It is possible to make in a few minutes with this apparatus and the aid of two cylinders of com- pressed air of 13 litres capacity, 100 ccm of liquid air. Steel Cylinders: see No. 55,099. If a compressor of at least 7 HP. is used instead of the steel cylinders it is possible to produce about 600 ccm of liquid air per hour with the apparatus. Prices of compressors quoted on'application. 55,103 a. Apparatus for the Liquefaction of Air and Hydrogen in large quantities, Figure, after Olszevski, for use with steel cylinders or with a compressor; with spare glass reservoirs Generates about 1 litre compressed air per hour with a 7 HP compressor and about 3 litres with a 19 HP compressor. 55, 103 b. Apparatus for the Liquefaction of Air in large quantities, Figure, entirely of metal in wood casing The output is the same as with No. 55, 103 a. 55, 103 c. Plate of Sketches for Explaining Linde's Counter-current Machine (M. T., S 68) . Liquid air can be obtained ready for use, ci. 6-213, immediately before using, from the suppliers. 70. ,->.-,. (i. 0. 3. 6555. No. 55 115. Liquefaction of Air. 611 55106. 1:10. 55113. 1:10. J 55 103 a. 1:7. 55103b. 1:6. 55115A. 1:8. 55115B. 1:6. Cylindrical Beakers with Evacuated Double Wall after Dewar, liquid air, liquid hydrogen, etc., silvered inside. Figure, for keeping cool £ »• List No. External Height, mm Internal Width, mm (a) .Beaker £ 55,104 160 35 0. 3. 6 55,105 250 40 0. 6. 0 55,106 350 60 0 10 0 55,107 400 75 0 15 0 55,108 300 100 120 (b) Polished Wood Base . . £ (c) Polished Wood Lid, lined with felt . £ 0. 1. 6 0.1.6 0.1.9 0.1.9 \J» J.V» V 0.2.0 0.2.0 V« At/* V 0.2.6 0.2.6 •*-• «v» V 0.3.0 0. S. 0 Flasks with evacuated Double Wall, silvered inside, for the same purpose, Figure. List No. 55,109 55,110 55,111 55,112 55,113 55,114 Capacity, approx. ccm 150 300 500 750 1000 2000 (a) Beaker £ 0. 3. 0 0. 3. 6 0. 4. 6 0. 6. 0 0. 8. 0 0. 16. 0 (b) Polished Wood Bases for same £ 0. 1. 6 0. 1. 9 0. 2. 0 0. 2. 3 0. 2. 6 0. 3. 0 55,115. Cylindrical Beaker after Weinhold, Figs. A & B, for storing liquid air, liquid hydro- gen etc. (W. D. 4th Edn. Fig. 407; Erdmann Anor. Chemie, Figs. 42 and 94), with evacuated quadruple wall and side tube on neck ; internal height 180 mm, internal width 35 mm, with base 1. 8. 0 Cl. 1827, 1826, 6556, 6557, 1828, 5566. 39* 612 Heat and Change of State. No. 55116 - 55 117. 1 : 5. 55 123. 3 : 4. 55 125. 1:16. 55 126. 1:10. 55.116. Double-walled Capsule for obtaining solid air by means of liquid hydrogen (Erdmann, Anor. Chemie, Fig. 43), 80 mm diameter 55.117. Lead Plate on Wood Base together with Hammer and Porcelain Bowl, Figure, for shewing the change in state of the lead plate when placed in liquid air (W. D., 4th Edn., Fig. 408) 55.118. 2 small Glasses, with Ether and Alcohol, in one cork mount, fitting cylindrical Beaker No. 55,115 (W. D., 4th Edn., Fig. 409) When plunged in liquid air the ether is converted into a crystalline mass: the alcohol first be- comes viscous, solidifying finally into a transparent mass. £ s. d. 0. 5. II 0. 6.0 0. 8.0 54,188. Hollow Cube of Crystal Glass, 8 cm side, for demonstrating the attraction of liquid air by an electromagnet (W. D., 4th Edn., p. 615) ................ I 0. 6. 0 A suitable Electromagnet to use is No. 62,280. 55,119. Apparatus for the Liquefaction and Freezing of Oxygen by the aid of liquid air (W. D., 4th Edn., Fig. 410) ........................... 1. 6.0 Ozone Tubes, for producing solid ozone by means of liquid air (W. D., 4th Edn., p. 619): sec Section "Electricity", p. 1017. 55.1-M. Apparatus after Erdmann for Freezing Water in liquid air (Erdmann, Anor. Chcmic. Fig. 97) ................................... 0.10.0 *5:>,iL'3. Apparatus for the Critical Temperature Phenomena, Figure (W. D., Fig. 365 [345]), with instructions for use, for objective projection ............. 0.0.0 * .">."). TJ.'Ja. Protecting Case for above of black sheet iron ................. 0. 11'. 0 I. Apparatus for the Liquefaction of Sulphurous Acid (W. !>.. Fig. 366 [346]) .... o. 4.0 :»."., I !'.">. Apparatus after Ndack for Liquefying Gases by Pressure and Cooling (Xtschr. z. Fonle- rung d. plus. I'.. 1886. p. UOS), simple pattern. Figure ............ 1.13. II # t';m be used with the Projection A|>|i;u iitns. Cl. 5596, 364, 1S21, 1825. Xo. 55 137. Liquefaction of Gases. Gas and Vapour Density. 613 55 136. 1 : 6. 55 137. 1 : 8. 55.126. Apparatus for the Liquefaction of Gases by Cooling, without the application of pressure, £ s. A. Figure 0. 10. 0 The lower part of the apparatus — the small flask — is placed in a cold mixture while the lower eduction pipe, which is provided with a U-tube connected to the small flask and is also surrounded by a cold mixture, is traversed by the gas being dealt with. The following are well adapted for this experiment: sulphurous acid, nitrous acid, ammonium cyanide and methyl chloride gas. 52,656. Piezometer inset with Four Tubes, after Magnus, for the liquefaction of Gases by pres- sure, Fig. 52,656, p. 359 (M. P., Ill, Fig. 306 [II, 2, Fig. 163]) 1.10.0 Three short syphon barometers are contained in one vessel and can be fed with mercury and various gases above the latter, while the fourth barometer serves as a manometer. 55.127. Carbonic Acid Gas Tube, appearing vacuous at ordinary temperature; only when cooled does some liquid carbon dioxide become visible. In box 0. 18. 0 55.128. - - i d e m, with perfectly anhydrous, pure carbonic acid 1. 5. 0 55.129. Carbonic Acid Tube with some liquid Carbonic Acid, Figure. At ordinary tempe- rature 2 — 5 ccm are visible, but when heated with the hand the tube appears empty. In small box .' 0.18.0. • >•>. 130. -- idem, with perfectly anhydrous, pure carbonic acid 1. 5. 0 55.131. Carbonic Acid Tube, about half-filled with liquid carbonic acid, for shewing the great mobility of the same. In case 0. 18. 0 55.132. -- idem, with perfectly anhydrous, pure carbonic acid 1. 8. 0 .V>, 133. Carbonic Acid Tube, entirely filled with liquid at 25° C. In case 0.18.0 55.134. - - i d e m, with perfectly anhydrous, pure carbonic acid 1. 8. 0 55.135. Tubes with Liquefied Gases: (a) Ammonia .... £ 0. 12. 0 (e) Carbonic Acid . £ 0. 18. 0 (i) Sulphurous Acid . £ 0. 10. 0 (b) Chlorine £0.12.0 (f) Nitrosy] Chloride £0.18.0 (j) Sulphuretted Hy- (c) Cyanogen .... £ 0. 18. 0 (g) Phosgene ... £ 0. 10. 0 drogen £ 0. 18. 0 (d) Carbon Oxysulphide £ 0.18.0 (h) Muriatic Acid . £ 0.15.0 (k) Nitrous Oxide . . £0.18.0 (1) Nitrogen Dioxide £ 0. 18. 0 55.136. Apparatus for Determining Gas and Vapour Densities by Dumas' Method, Figure, by (Iclermining the weight of a definite vapour volume (W. u. E., phys. Prakt., Fig. 56; Chwolson, I, Fig. 225) 1. 6. 0 1 Stand, 3 narrow-necked glass Flasks, 1 Thermometer, 1 Stirrer and 1 Wire Triangle. 55.137. Apparatus for Determining Vapour Density by Gay-Lussae's method, Figure (De- termination of Volume of the Vapour yielded by a given weight of Liquid), complete with stand, graduated tube, thermometer, stirrer and burner, but without mercury (M. P., Ill, Fig. 134 [II, 2, Fig. 142]) 3. 15. 0 Cl. 1809, 1822, 1810. 614 Heat and Change of State. No. 55 138 — 55138, 55139. 1 : 10. 55 140. 1 : 10. 55 141. 1 : 6. 55,138. Apparatus for Determining Vapour Density by A. W. Hofmann's method (Deter- mining the Volume of Vapour yielded by a given weight of Liquid) see Figure, with barometer tube, steam jacket, mercury bath, steam boiler, burner and small flask with glass stopper, stand and stage (W. u. E. phys. Prakt., Figs. 57 — 59; M. P., Ill, Fig. 135 [II, 2, Fig. 143]); without Mercury or Cooling Vessel £ s. d. 3. 0. 0 55.139. Cooling Vessel for above, see Fig. 55,138, of copper 2. 10. 0 55.140. Apparatus for Determining Vapour Density by the Air-displacement method of V. Meyer, Figure, with measuring glass for catching the gas and with water vessel (W. u. E. phys. Prakt., Fig. 60), without bracket 1.16.0 55.141. Effusiometer after Bunsen for Determining Vapour Density by the Efflux Met hud. Figure, with threeway cock and platinum diaphragm (W. u. E. phys. Prakt., Fig. 61 ; M. P. I, Fig. 574 [592]), without Mercury 2. 0. 53,143. -- idem, after Henniger, Fig. 53,143, p. 411 1. 6. Cl. 1811, 1812, 1813. No. 55 148 a. Vapour Density. Molecular Weight. 615 1 55 142, 54 874, 55 144, 51 727. 1 : 5. 55 146, 55 147, 54 874, 55 148. 1 : 5. Beckmann's Apparatus for Molecular Weight Determination by the Freezing Method, Fig. 55,142, improved pattern (Ztschr. fur phys. Chemie, 21, p. 239; W. u. B. phys. Prakt., Fig. 105), consisting of articles Nos. 55,142—55,144, 54,874, 51,727, 55,145. oo,142. Glass Cylinder with lid and stirrer, 4 air jackets, 2 freezing tubes, 3 filling pipettes, Figure . . 55.143. Platinum Stirrer, according to market price (Subject to fluctuation) . 54,874. Metastatic Thermometer after Walferdin, divided in 0,01° C., see Fig. 55,142 55.144. Electromagnet, see Fig. 55,142 51,727. Metronome with electric contacts, see Fig. 55,142 The use of a thermopile, as the illustration shews, is only necessary when no other electric source is available. Prices of thermopiles are given in "Electricity" Section. 55,145. Pastille Press with steel mould Beckmann's Apparatus for Molecular Weight Determination by the Ebullition Method, Fig. 55,146, also in improved pattern (Ztschr. fur phys. Chemie, 21, p. 245; W. u. E. phys. Prakt., Fig. 109), for solvents with a boiling point to about 130° C., comprising articles Nos. 55,146—55,148, 54,874. r)j,14(i. Boiling Tube with internal cooler and ground-on stopper, 2 air jackets with mica slab, stand on tripod with clamp, sleeve, ring with asbestos wire net, Figure 55.147. Micro Gas Burner, see Fig. 55,146 54,874. Metastatic Thermometer after Walferdin, divided in 0.01° C., see Fig. 55,146 55.148. Platinum Tetrahedron, according to market value; about 8 — 10 g platinum tetrahedron is necessary, see Fig. 55,146 55,148 a. Reduction Table for Gas Volumes measured wet, after Friedr. C. G. Miiller (Ztschr. f. d. phys. u. chem. U., 23, 1910, p. 354), magnified five-fold £ s. d. 0. is. o 2. o. o 1. 10. o 0. 15. 0 1. 5. 0 1. 4. 0 1. 0. 0 0. 6. 0 1. 10. 0 Price on appli- cation 1. 8. 0 Cl. 1829, 1830. 616 Specific Heat. No. 55 149 — 55152. 1 = 11. 55 151 B. 1:5. 55 151 C. 1:5. Specific Heat. Calorimetry. Determination of Calorific Value. 55.149. Apparatus after Tyndall for Shewing the Relative Magnitude of Specific Heat of Dif- ferent Metals, Figure (W. D., Fig. 385 [365]; M. P., Ill, Fig. 97 [II, 2, Fig. 175]), with five metal spheres of iron, zinc, copper, bismuth and lead, tripod and six paraffin slabs 55.150. - - i (1 e in, after Kolbe, Figure, with device for scraping the spheres, heating vessel, tripod and glass cylinder with vaseline mixture for catching the heated spheres of iron, zinc, copper, bismuth and brass (Ztschr. f. d. phys. u. chem. V., 14, 1901, page 160) 55.151. Apparatus for Specific Heat, after Schoentje-s, Figs. A, B and C (Ztschr. f. d. phys. u. chem. U., 14, 1901, p. 31) . . . The apparatus comprises four parts: a gas burner, a easting mould for paraffin slabs, Fig. A; a heating vessel, Fig. B; and tin; main part — a stand and a frame with four cylinders (of the same weight), of iron, brass, tin and lead, which are of the same external diameter and the same height and which are fastened on sliding rods, Fig. C. After the cylinders have been sufficiently heated in the bath. Fig. B, the frame is placed on the stand in which ft paraffin slali has been fixed'; the cylinder- arc then allowed to fall simultaneously on the slab by releasing a catch. The four cylinders then sink into the slab to different depths in proportion to their specific heat (see Fig. C). :>.">. 1 .")!'. Ice Calorimeter after Lavoisier and Laplace, Figure (M. P., Ill, Fig. 99 [II, 2, Fig. 177]; Gan.-Eein., Fig. 426; M. T., p. 151) -,:,,! 53. _ idem, after Bunsen, Figure (M. P., Ill, Fig. 101 [II, 2, Fig. 179]; Gan.- £ s. d. .Man., Fig. 528; Gan.-Eein., Fig. 427) 0.12.0 1. -2.0 3. 5. 0 2. 0. 0 1. Mi. 0 Cl. 1833, 1334, 1836, 1833, 1835,1837. N.I. :,5164. Calorimeters. 617 55 157. 1 : 4. 55 158. 1 : 2. 55.154. Ice Calorimeter after Eeichert, F i g u re , for lecture purposes (Fr. phys. Techn., I, 2, Fig. 3091 [I, Fig. 391]) ' 55.155. Heating Apparatus for Calorimetric Experiments, after Eegnault (M. P., Ill, Fig. 104 [II, 2, Fig. 182]; Gan.-Eein., Fig. 428), with tripod and burner 55.156. - - idem, after Pfaundler, Figure (W. u. E. phys. Prakt,, Fig. Ill) .... 55.157. Heating Apparatus after Pettersson, Figure, of copper (W. u. E. phys. Prakt., Fig. 112) .Vi.l58. - - idem, after Neumann (Neumann's Tap), with thermometer, Figure (M. P., Ill, Fig. 114 [II, 2, Fig. 192]; W. u. E. phys. Prakt., Fig. 113), very neatly constructed of brass Metallic Bodies after Bebenstorff, for determining Specific Heat and proving Dulong und Petit' s Law, calibrated to 10 grammes atomic weight. Material Zinc Aluminium Magnesium Tin Cadmium List No. 55,159 55,160 55,161 55,162 55,163 £ 0. 8. 0 0. 11. 0 1. 0. 0 0. 14. 0 1. 10. 0 ."i5,l<>4. Semi-cylindrically bent Plates with eyes, of lead, copper and iron, with boiling flask for 1 kg mercury, for determining Specific Heat by the Mixing Method (M. T., p. 148) Cl. 1839, 1840, 1842, 1843. £ 8. d. 0.15.0 1. 0.0 1. 0.0 1.13.0 3.12.0 . 0. 12. .0 1841, 618 Specific Heat. No. 55 165 — 55 170. 55.165. Calorimeter Vessel after Friedr. C. G. Miiller (M. T., Fig. 98), capacity 1.2 litres 55.166. --idem, 1/t litre capacity 55.167. Calorimeter after Weinhold, Figs. A and B (W. D., Figs. 386 and 387 [366 and 367]), with heating vessel, double-walled measuring vessel and cylindrical test piece 1/2 kg weight for determining the specific heat of a metal, the latent heat of melting of ice, and - - in conjunction with No. 55,168 - - the latent heat of vaporisation of water . 55.168. Water Trap for No. 55,167, for keeping the water of condensation from the calori- meter in the experiment on the latent heat of vaporisation (W. D., Fig. 389 [369]) . 55,160. Water Calorimeter, Figure, for determining Specific Heats by the Mixing Method, with thermometer divided in 0.2° 55,170. Double Calorimeter, Figure, for rapidly comparing the specific heat of two bodies, with two test pieces of brass and lead of the same weight, two thermometers and steam- heating vessel for two bodies .">r». 171. 3 Test Pieces of Copper, Iron and Zinc, of same weight .V>. 171'. Calorimeter after Wiedeniann and Ebert, with wood block, stirrer, double-walled sheathing vessel and cover (\V. u. E. phys. Prakt., Fig. 114) .V>.17:!. Calorimeter after B^gnault, Figure, with two thermometers divided in 0.5°, for solids and liquids (M. I'., Ill, Figs. Ill and 112 [II, 2, Figs. 189 and 190]) .... Cl. IS 14, 1815, 1846, 5783, 1848. £ 8. d. 0. 10. 0 0. 8.0 0.18.0 0. ;:. u 1. •!.(> 2. 8.0 0.18.0 1. LM) 4. 4.0 1853, No. 65178. Calorimeters. 619 55 177. 1 : 10. 55 175. 1 = 9. 55 176. 1 : 8. 55.174. Mercury Calorimeter after Favre and Silbermann, Figure (M. P., Ill, Fig. 119 [II, 2, Fig. 197]), on polished oak stand; all metal parts of iron and heavily nickelled. Glass bulb 130 mm diameter, embedded in insulating material; capillary in front of a millimetre ssale 500 mm long; with two retorts but without mercury 55.175. Calorimeter for Liquids after Wiedemann, Figure, consisting of a double-walled heating vessel with iron cylinder for taking mercury; with steel cock and, underneath same, a flat, hollow metal screen for holding off the heat rays; double-walled calori- meter with lateral thermometer, fixed on a slider movable in the base of the apparatus (Fr. phys. Techn., I, 2, Fig. 3074) 55,176. Calorimeter for Liquids, the mixing method . . . Figure, after Eegnault, for determining specific heat by 55.177. Calorimeter for Liquids, after Kopp, Figure (W. u. E. phys. Prakt., Fig. 194) One filling vessel with wire holder, six glass vessels (long necked) for the liquids, one small base for same for holding when weighing; one calorimeter vessel of brass with wood block and stirrer, one iron mercury-vessel with wire triangle and glass stirrer, one double-walled sheathing vessel of brass with cardboard lid, one stand with two holders and one ring, and one thermometer. 55.178. Calorifere after Andrews, modified by Pfaundler, Figure (M. P., Ill, Fig. 118 [II, 2, Fig. 196]; W. u. E. phys. Prakt., Fig. 115) The bulb is 44 mm diameter and holds 606 g mercury; the space between the two marks m and m' holds 6,8 g mercury. £ s. d. 4. 0.0 7. 0.0 12.10.0 2. 8.0 0. 15. 0 Cl. 1851, 1853, 1819, 4502. 620 Specific Heat. No. 55 179 — 55 179. 1 : 0. 55 181. 1 : 15. 55182. 1:14. 55 183. 1:10. 55.179. Calorimeter after Dulong and Petit, for the radiation method, Figure (.M. P., £ s- d- III, Fig. 124 [II, 2, Fig. 201]; W. u. E. phys. Prakt,, Fig. 117), with niekelled radi- ation vessel ;ind thermometer 1.1 2. 0 55.180. Calorimeter after Weinhold, for high temperatures (M. P., Ill, Figs. H'7 and 128 [II, -, Fi.u>. -53. No. 55 187. Calorimeters. 631 '55185. 1:8. 55 187. 1 = 6. 55.181. Apparatus after De la Eoche and Be"rard, Figure, for determining the Specific Heat of Gases at Constant Pressure (M. P., Ill, Fig. 129 [II, 2, Fig. 205]) 55.182. Gas Calorimeter after Be'gnault, for the same purpose, Figure (M. P., Ill, Figs. 130 and 131 [II, 2, Figs. 206/7]; Gan.-Kein., Fig. 433) 55.183. Calorimeter after Eilhard Wiedemann, for determining the Specific Heat of Gases at constant Pressure, Figure (Pogg. Ann. d. Phys. u. Chemie, Vol. 157, 1876, p. 1; .M. P., Ill, Fig. 132 [II, 2, Fig. 208]) The illustration includes only the Heating Apparatus with Water Bath and the Calorimeter. The following pertain to the complete apparatus: 1 flask with rubber ball, 1 water flask with tube and lead pipe, 1 large glass flask. -2 manometers, thermometer screen with thermometer. The heating bath has a stirring device, 1 thermometer and 1 burner; while the calorimeter vessel contains a measuring vessel with three small silver cylinders, filled with silver turnings. Given in is one thermometer divided in Vio" C. 55.184. Pendulum Clock with electric 1/4-minute contact, for calorimetric work, mounted open, at same time serving as model of a pendulum clock, see Fig. 52,428, p. 333 .• Chronoscopes: see p. 248. .">.">. I S5. Apparatus after Clement and De"sonues, Figure, for determining the Specific Heat of Gases at Constant Volume (M. P., Ill, Fig. 133 [II, 2, Fig. 209]), also for shewing the temperature change on the expansion and contraction of gases (W. D., Fig. 416 [392]) £ s. d. 12. 0.0 15. 0.0 17.10.0 3. 0.0 1.16.0 .">.•"). isii. Calorimeter after Brix, for determining Heat of Vaporisation, Figure (M. P., Ill, Fig. 371 [II, 2, Fig. 227]) 1. 10. 0 55,187. Calorimeter after Schiff, for determining Heat of Vaporisation, Figure, with thermo- meter, flask, stand, tripod, and wire netting (W. u. E., phys. Prakt., Fig. 124) ... 4. 0. 0 Cl. 1858, 1859, 1860. 622 Specific Heat. Determination of Calorific Value. No. 55 188 — 55 188. 1 : 5. 55 189. 1 : 6. 55 192. 1 : 7. 55 191. 1 : 6. 55 193. 1 : 7. 55,188. Berthelot's Apparatus for determination of the total Heat of Steam, F i g u r e (M. P., * s <'• III, Fig. 370 [II, 2, Fig. 226]; Gan.-Man., Fig. 530; Gan.-Eein., Fig. 435) 3. 0. 0 .").">. 1 89. - - idem, electrically heated, Figure, for connecting up to 65 — 220 volts, without current regulator 4. 4. 0 Current Regulator: (a) for 65 V., £ 1.16.0; (b) for 110 V. £ 2.6.0; (c) for 220 V., £ 3.6.0. 55,190. Apparatus for determining Calorific Value of Hydrogen (Calorimeter) after Friedr. C. G. Miiller (M. T., p. 148 and Fig. 245 on p. 351), consisting of an apparatus for t1u> Synthesis of Water o. 1C. 0 55,191. Demonstration Calorimeter after Friedr. C. G. Miiller, Figure, for determining the Calorific Value of solid fuels such as charcoal, lignite, wood (M. T., Fig. 106), of glass 0. 14. 0 Cl. 1861, 3888, 18G2, 5405, 5018. No. 55 199. Calorimeters for Calorific Value Determinations. 623 55 199. 1 : 3. E5 194, 55 195, 55 197. 1 : 55.192. Calorimeter after Favre and Silbermann, for determining the Heat of Combustion of solid and liquid fuels at constant pressure, Figure (M. P., Ill, Figs. 377/80 [II, 2, Fig. 231]) The apparatus consists of a double-walled outer vessel with cock, which is filled with water. In this vessel is contained, insulated by a cork, the calorimeter vessel, which likewise should be filled with water. The combustion vessel is freely suspended in a calorimeter vessel. The combustion vessel possesses a gas lead, an oxygen lead, and a tube with spiral for carrying off the gases of combustion. In the combustion vessel it is possible to suspend one Platinum Crucible, with sieve bottom for burning coal, one Porcelain Crucible for burning sulphur, and one small Flask for the combustion of liquids; these three items are supplied with the apparatus. The combustion vessel is closed by a glass above which is a mirror for observing the process of combustion. All metal parts of brass. 55.193. Demonstration Calorimeter after Eumford, Figure, for determining the Calorific Value of liquid fuels (Fr. phys. Techn., I, 2, Fig. 3158) 55.194. Calorimeter after Parr, Figure, for technical Calorific Value determinations of fuels, with Sieve, Eeagent Flask with rubber stopper, Measuring Beaker, 12 small Ignition Eods, Tongs, Magnifier with stem, Spanner, and high-grade Thermometer divided in Vso0 C. Price without motor or driving stand The calorimeter supplies a convenient, cheap, reliable and indispensable means for officials and manufacturers for carrying out comparative determinations of the value of fuels (lignite, coal, coke, etc.) employed. An experiment, including the necessary weighings, occupies but half an hour. In this appa- ratus high pressure is neither used nor is it produced in the reaction, as a chemical auxiliary reagent gives the necessary oxygen for the combustion and, on the other hand, binds the products of combustion. Complete description and instructions for use gladly sent on application. Accessories for the Parr Calorimeter: see Nos. 55,195 et seq. 55.195. Electric Motor for 110 Volts D. C., with driving stand, see Fig. 55,194 . . . If type of current or voltage differ from above, prices vary accordingly. 55.196. Turbine after Eabe, with driving stand, for connecting to the water lead . . 55.197. Spare Cartridge (Reaction Vessel), see Fig. 55,194 55,198. Spare Thermometer, divided in 0.02° C., with value for water given 51,546. Chemico-technical Balance in glazed walnut case, with arrestment and levelling screws, sensitivity 1 mg, to carry 20 g, cf. Fig. 51,548, p. 234 £ s. d. 11. 0. 0 151,622. Set Of Weights, from 1 mg to 20 g, of brass, gilt 55,199. Steel Cylinder for Calorimetric Experiments, after Dr. Koneck, Figure 2. 4. 0 10. 0. 0 3. 10. 0 1. 5. 0 1. 11. 0 1. 10. 0 2. 0. 0 1. 0. 0 2. 0. 0 Cl. 1863, 3420 a. 624 Technical Calorimeters. No. 55 200 — 55200 — 55211. 1:15 55 211. 1 : 5. 55204,55212. 1:15. 55.200. Calorimeter after Junkers, Figure, for technical Calorific Value Determinations of Gases and, in connection with auxiliary outfit No. 55,213, for calorific value determina- tions of Liquids, of copper and brass, carefully nickelled, with gas burner For Accessories see Nos. 55,201 — 55,213. The apparatus works continuously (since combustion is continuous), and even in the open air and, in view of the fact that a steady flow of water is used which carries from the instrument in each moment as much heat as is conducted into it. Two thermometer readings and the determination of gas and water volume suffice for estimating the calorific value. This can be done even by the unskilled and with an accuracy which attains, if not surpasses, the best of the scientific methods used up to now. The calorimeter consists essentially of a special tube boiler which, while very compactly constructed allows the flame sufficient room to expand and permits of complete combustion, while at the same time it effects very energetic cooling of the gases in such a way that the heat is entirely taken up by the water current. At the same time sufficient draught is produced. The regularity of the water flow is secured by a special arrangement serving to keep the pressure of the water perfectly constant. A cock permits of adjusting the strength of the water flow and consequently of varying the temperature of eduction. By means of a throttle valve fitted in the flue it is possible to regulate the quantity of air necessary for combustion. In order to avoid the absorption and emission of heat at the surroundings, the calorimeter is covered by a well-polished nickelled jacket. Between the two is a still stratum of air. Thermal trans- mission is therefore reduced to the lowest minimum and can even be avoided altogether by making the mean temperature of the instrument equal the room-temperature, which can easily be done by the regulating cock mentioned above. After the calorimeter is started, the water placed in it and the burner introduced, the steady state is attained in a few minutes and the measurements can be proceeded with. 55.201. 2 Thermometers for 0° to + 50° C., divided in >/10° Each £ 0.7.6 55.202. 2 Magnifiers for reading Each £ 0. 7. 6 55.203. Case for the Calorimeter, very neat pattern 55.204. Gas Meter for 3 litres. Figs. 55,200 and 55,204 55.205. 2 Thermometers for 0° to + 50° ('., divided in whole degrees Eacli £ 0.2.6 55.206. Cylindrical Glass Measure for 2000 ccm, graduated every 20 ccm, for measuring the eduction water 55.207. — idem, for 100 ccm, divided in ]/i ccm, for measuring the condensing water 55.208. Case for the Gas Meter 55,2O!I. 4 Rubber Stoppers fur inserting the thermometer 55,21(1. 5 m Rubber Tubing .V,.:MI. Gas Pressure Governor, of bra.-, finely niekelled. with reservoir. Figure, with (i l.rass plates and 1 extra valve .V>.-M_! Gas-Meter Calibrating Device, !•'!«•. .">">. 204, for 1 litre calibration-volume, consisting of calibration fla-k. liras.- stand, nicely nieUelled. and water vessel, without gas-meter .•>.-).213. Auxiliary Outfit for Calorific Value determinations of liquid fuels. Figure The outfit consists of a Precision Balance, 1 Carburetting Lamp for liquid fuel- and 1 extra Burner Head for spirit. £ s. d. 17. 0. 0 0. 15. 0. 15. 1. '2. 4. 16. 0. 5. 0. 7. 0. -2. 0. 17. i). 1. 0. 7. •2. I.'., 3. 15. 8. H. . 0 Cl. 1SU4, 18(15. 1866. No. 55217. Calorimetry. 625 55213. 1:15. 55 217. 1 : 8. 55 214. 1 : 10. 55,214. Calorimeter after Bertholet-Mahler, improved by Kroeker, Figure, for calori- nictric determinations by means of a combustion bomb, for Technical Purposes . . . The apparatus consists of a steel bomb 300 com content, enamelled inside, polished and nickcllcd outside, with insulated platinum pole and platinum tube carried to the bottom of the bomb; Stirrer arranged for hand and motor drive; a nickelled Water Vessel with oak insulating jacket and thermo- meter holder; a Thermometer divided in Vso0 C.; a Manometer on stand with parts for connecting to the bomb and to the oxygen cylinder; a Steel Mould for making coal briquettes; a Support for the Bomb for use while screwing down the lid; a Clay Capsule; various spanners; a Valve Adjusting Pin ; Ignition Wire and spare Lead Packing Rings. The bomb is filled with oxygen from a steel cylinder; this should be ordered separately if not available. 55,215. -- idem, for Scientific Use This apparatus differs from the preceding in that the inner surface of the bomb lid is coated with platinum iind that the valve points are of platinum-indium. Instead of the clay capsule there is a Platinum Crucible with platinum holder and clamping screw. The insulating vessel consists of ;i double-walled copper jacket and should be filled with water at room temperature. The thermometer is divided in Vioo" C., is provided with a Test Certificate from the Physikalisch-Technische Reichs- anstalt, and has a magnifier for reading. 55,2 1<». Apparatus for determining the Generation of Heat by the simple Mixing of different Liquids, after Bussy and Buignet, Figure, with thermometer divided in 0.2° C1. . £ s. d. 24. 15. 0 Liable to alteration owing to fluctuating price of platinum 38. 10. 0 Liable to alteration owing to fluctuating price of platinum 3. 15. 0 >5,217. Apparatus for determining the Heat of Neutralisation on mixing Acids and Bases, Figure (W. u. E., phys. Prakt., Fig. 126) 1. 4. 0 Cl. 1867, 1863, 1869, 41G3. 40 626 Heat and Work. X(,. .-.•_> (US — 55 218. 1 : 9. 55 220. 1 : 9. 55 221. 1 : 3. Heat and Work. £ s. d. 52.048. Apparatus for boiling Water, Alcohol or Ether by Friction; for the whirling table (W. D., Fig. 417 [393]; Gan.-Eein., Fig. 451) 0. 5. 0 52.049. - - i d e m, with arrangement in order to enable the spirit of wine to be ignited, Fig. 52,049, p. 285 0. »>. o 55,185. Apparatus for showing Temperature-change on Expansion and Contraction of Gases, Fig. 55,185, p. 621 (W. D., Fig. 416 [392]), and for determining the specific heat of --uses at constant volume 1. K'.. u 55,218. Apparatus for showing the Temperature-change on the Compression and Expansion Of Gases, after Tyndall, Figure (Tyndall, Die Warme [Heat], Fig. (i, p. IcS; Gan.- Man., Fig. 546; Gan.-Eein., Fig. 464) 2.10.0 1st Experiment. Air at the temperature of the surrounding space compressed in the vessel some hours previous to the experiment shows a cooling effect whan flowing against a thermocouple. 2nd Experiment. If air which has just been compressed in the flask and thereby become heated is allowed to flow against a thermopile, the latter indicates heat; on repeating this a number of times this heat is exhausted and the galvanometer pointer finally shows cold. 55.220. Apparatus after Favre and Silbermann, for showing Heating of the Air on Compression and Cooling on Expansion, Figure, with .sensitive spiral thermometer (M. P., Ill, Fig. 400 [II, 2, Fig. 248]) (i. Hi. 0 A pointer is suspended on a Breguet platinum-silver spiral, above a graduation, in a glass vessel which is in direct communication with the pump cylinder (ef. Pig. 54.SIH1. p. 581). This sensitive thermometer shows the increase of temperature ensuing when the air is compressed by pressing down the piston, and, inversely, the lowering of the temperature on rarifying. 55.221. Apparatus after Behrendsen for the same purpose, Figure, with stoprock and base for setting up on the air pump 1- I. A thermocouple is contained in the upper part of the apparatus, its ends leading to two terminals tor the galvanometer lead-. 55.222. Pneumatic Fire Syringe, of metal, Figure (Gan.-Man., Kig. 5-15; Gan.-Atk.. Fig. 452) 0. 7. 0 55,22.".. -idem, of glass. Figure , 0.16.0 The syringe is constmete:! in such mn-incr tli.it the luminous phenomena occurrim; on ignition can plainly be seen through the glass. To make the experiment, the syringe should be pressed firmly against the wall of lecture table with the left hand and the piston pressed in smartly with the light hand, being drawn out immcdiat-ly so that the tinder continues to smoulder. The slow match must be quite dry and hav'e been previously ignited and extinguished once. 55.22-1. Apparatus for showing the Action of Gunpowder, after Friedr. 0. (i. Miiller (Ztsrhr. f. d. ph.ys. 11. di.Mii. U., 2, p. 170; M. T., Fig. 89) 0. 1". » Cl. 1871, 1873. 1874. \,.. .-,:, i'.'T. Heat on Compression. Mechanical Equivalent of Heat. 627 55 222. 1:4. 55 223. 1 : 4. 55 226. 1 : 9. 55225. 1:7. 55 227. 1 : 10. 55.L'L'5. Gore's Ball, Figure, rotating by heat (Eisenlohr, p. 532) The ball, 30 mm diameter, is solid so as to ensure good contact. If the ball and the track are well polished the experiment acts very well with an accumulator cell or a good Bunsen cell. 53,199. Trevelyan's Rocker: see Pig. 53,199, p. 420 For other patterns, see Xos. 53,200/1, p. 420. .").:, 050. Apparatus after Puluj, for determining the Mechanical Equivalent of Heat; for placing on the whirling table, F i g. 52,050 p. 285 52.051. -- idem, with Whirling Table No. 51,949 55.226. - - i d e m, with large Driving Stand, Figure, and with thermometer divided in V10° (W. D., Figs. 418 — 421 [394—397]; M. P., Ill, Fig. 406 [II, 2, Fig. 254]) . . . The inner cone is completely insulated by ivory. The type of instrument is excellent, and the experiment can be carried out with great accuracy. The driving stand can be used as a whirling table on removing the device for Puluj 's experiment. Km Patterns with Electric Motor drive, also Accessories for same, see under Nos. 52,052— 52.055 and the illustrations on p. 286. 55.227. Apparatus after Grimsehl, for Determining the Mechanical Equivalent of Heat, F i- g u r e, witli manometer, which serves as an air thermometer (/tsehr. f. d. phys. u. chem. I"., 16, 1903, p. 290), with cramps for screwing to the lecture table £ s. d. 1.14.0 0. 15. 0 5. 5.0 7. 0.0 9. 0.0 ' 3. 10. 0 f.'l. 1013, 1014, 1877,3861. 4102, 40* 628 Heat and Work. No. ">."> 228 — 55 232 B. l . lo. 55 232 A. 1:15. CI. 3420*. 1886. S230, 1880, 4204. . 55242. Mechanical Equivalent of Heat. Heat Engines. 629 55 241. 1 : 4. 52,228. Apparatus after Christiansen for determining the Mechanical Equivalent of Heat, £ »• (1 F i g u r e (M. P., Ill, Fig. 407 [II, 2, Fig. 255]; W. u. E. phys. Prakt., Fig. 121), with 110 volt D. C. motor, the accuracy of the apparatus is about 1% 16. 0.0 55,230. Apparatus after Callendar, Figure, for determining the Mechanical Equivalent Of Heat, driven by a 110 volt D. C. Motor.1 Including motor 16. 0. 0 The work of friction is generated by loaded silk brake bands laid round a rotating cylinder of thin luass filled with a certain quantity of water. The heat is measured by a thermometer introduced through a central aperture into one of the cylinder bases. The number of revolutions is indicated by a speed connter. Thermal loss can be eliminated by Rumford's compensation method by two measurements with different load. The lecturer can obtain values accurate to approx. */s% in the presence of the audience within 10 minutes. .V>. 231. -- idem, for working by hand, without motor 12.10.0 .V..232. Apparatus after Joule, Figs. A and B, for determining the Mechanical Equivalent Of Heat (M. P., Ill, Figs. 404/5 [II, 2, Figs. 252/3]; Gan.-Man., Fig. 517; Gan.-Bein., Fig. 462), with Wood Stand and vertical rules |l6. 0.0 Heat Engines. Hot Air Engines with Ribbed Cooler. F i g. 55,234. List Xo. 55,233 55,234 55,235 55,236 55,237 55,238 55,239 55,240 Piston Diamr., . mm 30 Flywheel Diamr., mm 118 Efficiency ... HP V,M (a) Spirit-heated . £ 1. 16. 0 (b) Gas-heated . . t (c) Petroleum-heated£ — 40 54 65 80 170 200 260 330 /BO 4. 10. 0 /40 6. 10. 0 V» 9.0.0 V» 13. 0. 0 4. 10. 0 5. 15. 0 8.0.0 12. 0. 0 100 410 V, 18. 10. 0 17. 10. 0 33. 10. 0 41. 0. 0 19. 10. 0 37, 0. 0 45. 0. 0 130 550 V* 150 590 91 This hot-air engine forms a very simple, cheap and safe motor. The ribbed cooling replaces the water-cooling adopted in other hot-air engines and their attendant disadvantages and simplifies the manipulation of the motor in that it is only necessary to light the heating jet — spirit, gas, petroleum or petrol — for starting. 55,241. Instructional Model of a Gas Engine after Eichter, Figure (Ztschr. f. d. phys. u. chem. U., 12, 1899 p. 265) 3. 4.0 The model explains the mode of action of a 4-cycle gas engine. The four cycles of the motion of the piston, also Ignition and gearing can easily be explained. It is possible to set the model in motion (it cannot be worked) by a handle fixed to the flywheel. 55,242. Model of a Horizontal Gas Engine, Otto system, 1/10 HP; see Fig. 55,243, p. 630, working as a 4-cycle motor with electric ignition, for house gas or petrol 18. 0. 0 Dimensions: bore 50 mm, flywheel diam. 400 mm, speed 800 r.p.m., gas-consumption 300 litres per hour. The following pertain to the engine: 1 gas bag, 1 cooling vessel, 1 ignition coil, 1 double cell, o leads, 2 spanners. 1 With motor working at other current or voltage at corresponding variation in price. When ordering, pe of current and voltage should be mentioned, and in the case of 3-phase current, the frequency. Cl. 1887. 630 Heat and Work. No. .V, -Jl.'! 55 249. 1 : 5. 55 250. 1 : 6. 55 251. 1 : 7. .v>,:M.'3. Gas Engine No. 55,242 with Dynamo, mounted on one baseplate, Figure, with glow lamp on stand •-!. o. <> The generator pves -2 amps, at 12 volts. r».U<)l. Steam Reaction Wheel (Heron's Rotating Sphere), of glass, in iron stand, Fig. 53,101. p. 407 0. 5. 0 :..; loi>. Steam Reaction Wheel, entirely <>r metal, Fig. 53,loi>, p. 407 o. ll.it :..VJ14. Aeolipile, \vitli safety valve (Fr. phys. Teehn., I, 2, Fig. 3668) 0. 1S.O .V>.L' 15. Model Geyser after Wiedemann, Figure :i|>]iar!ilns >h t hr ]ilic-nomena of the throwing >i]> of liol water and steam. Cl. 1888, 1883, 3810, 1882, 34'21, IJ'i-.1. No. Heat Engines. 631 55 253. 1 : 7. 55 254. 1 : 4. 55 255. 1 : 6. 55.246. Apparatus for demonstrating the Geyser, after Tyndall, Figure (Tyndall, Die Warme [Heat], 4th Edn., 1894, Fig. 54), for gas heating The apparatus is heated by placing a Bunsen burner underneath and by the gas ring given with the apparatus, and shows an eruption about every minute. 55.247. Steam Piston, for showing the action of Water Vapour, of glass, with holder . . . 55.249. -- idem, Figure, of Metal, with handle 55.250. - - i d e in, larger, Figure, of glass, with metal mounts and handle, on stand 55.251. Sectional Model of a Steam Engine Cylinder, Figure, with Slide Valve gearing, large type, of Metal 55.252. Sectional Model of a Steam Engine Cylinder, Figure, with flywheel, entirely of metal, cylinder bore 36 mm, length 80 mm .">"). 253. - - i d e in, Figure, with governor and throttle valve #55,254. Sectional Model of a Steam Cylinder, Figure, transparent, for projection . . . The path of the steam can be demonstrated by blowing in some cigar smoke. 55,255. Sectional Model of an Oscillating Steam Engine Cylinder, Figure, movable, of wood and iron £ s. d. 2.16.0 0. 3.0 0. 8.0 1. 4.0 2. 4.0 2. 2.0 4. 4.0 2. 6.0 4.16.0 * Can be used with the projection apparatus. Cl. 1890,4200, 305, 3957. 632 Heat and Work. NIL .'.:. •_• ifl 55257. 1:10. 55 262. 55 263. 1 :.:•. LT»(>. Sectional Model of a Cylinder with simple Slide Valve, F i g u r e, of wood .V>._':>6 a. - - i (1 c in, of iron, smaller, about 3/s the si/e , :•:.. -':>7. - idem, with Farcot Slide Valve, F i $ \\ r e, of wood •V..258. - - i d e m, of iron, smaller, about :! . the si/e 55,2f>!t. - - i d <• MI, with Meyer Compound Slide Valve, F i :>.•_'<>!. -- idem, with Rider Slide Valve, Figure, of iron 55,262. - - i d e m, with Woolf Slide Valve, F i . (I 6217, 4899, IN'.i.l. BM1, 3691, 1884 s. d. 0. 0 0. 0 0. (» 0. d 0. 0 0. 0 d. 0 0. U 0. 0 0. (I No. 55 -Ji;!'.. Steam Engines. 633 55 264 A. 1:16. 52266. 1:7. 55264B. 1:16. 55264C. 1:16. 55 265. 1 : 5. 55 266. 1 : 4. 55.264. Sectional Model of a Steam Engine Cylinder, after Prof. Vater, Pigs. A, B ana C, large plainly understandable model, with adjustable advance and eccentricity, with inter- changeable cylinder and valve parts for the ordinary three-port slide valve, Fig. A, the double-inlet channel slide-valve, Fig. B, and the Penn slide valve with double port for inlet and exhaust, Fig. C, painted in clear colours . . " 52,266. Sectional Model of a Steam Engine Cylinder with Slide Valve and Link (reverse gear for locomotives), after Stephenson, F i g u r e, of iron (Gan.-Man., Fig. 569) .... 55.265. Sectional Model of a Horizontal Steam Engine, F i g u r e, of metal, with valve gearing, governor and throttle vavle 55,266. Sectional Model of a Compound Steam Engine, Figure £ s. d. 15.0. 0 12.0.0 3. 4. 0 15.0.0 The high and low pressure cylinders, the simple slide valve motion and the receiver are repre- sented in section. Cl. 6037, 532, 6035, 1895, 18!W 634 Heat and Work. 55 268. 1 : 7. 55 269. 1 : 7. 55 270. 1 : 12. 55 271. 1 : 5. 55,268. Model of a Watt Low-pressure Engine, of metal and cardboard, movable, Figure 1. .V..-J6J). Sectional Model of a Watt Low-pressure Steam Engine, F i g u r e, of metal; showing in section the cylinder, valve-chest, condenser and pumps; cylinder bore 32 mm . . 11. 55,270. High Pressure Iron Boiler, Figure, after Friedr. C. G. Miiller, for 6 Atmosphere* (M. T., p. 165), with Fletcher gas-burner, water gauge, discharge-cock, pressure-gauge. .-upports tin I In- check manometer, safety valve, steam pipe cock and feed pump . . IS. .V>.L'71. Model Steam Engine, Figure, with brass boiler. Bafetj \alve. water discharge- cock, testing cock, steam pipe cock, water gauge, whistle, pressure-gauge and feed pump; also with a complete sectional model of a steam cylinder. With gas burner .... 11. 8. (1. .">.»> 0.0 Fitted, it clcMivd. uitli spirit Inirner in place of the gas burner. 01. 1897, 1880, 5836,1899. No. ;>527S. Steam Engines. 635 55274 (55272, 55273). 1 : 8. 55275. 1:10. 55 272. Model of a Horizontal Steam Engine, cf. Fig. 55 272, without boiler Dimensions: piston diam. 40 mm; stroke 60 mm; flywheel diam. 330 mm; length, breadth and height of the entire engine 660 x 310 x 340 mm. 55,273. Boiler for above, of Copper, with Safety Valve, pressure-gauge, water gauge, test cocks, check valve, whistle; can be heated with gas or spirit; length 500 mm, diam. 220 mm, cf. Fig. 55,272 .">:>. 274. Steam Engine No. 55,272, with Boiler No. 55,273, both built on to one baseboard, Figure r>.">,275. Horizontal Steam Engine, Vio HP, with Cylindrical Boiler and Dynamo, Figure The. illustration shows a single tube boiler. Instead of this, however, a simple cylindrical boiler is supplied. Size of boiler: length 600mm, diam. 220mm. Dimensions of engine: piston diam. 55 mm, flywheel diam. 400 mm. Output of dynamo: 2 amps, at 10 volts. Ci. 1900, 1901. £ s. d. 9. 0. 0 10. 0. 0 20. 0. 0 30. 0. 0 636 Heat and Work. 55 276. 1 : 9. 55 277. l : 0. 55278. 1:10. 55,276. Watt's Low-pressure Engine with Condenser, Figure, with Boiler No. 55,273; £ s «'• piston diam. 40 mm; stroke 80 mm; flywheel diam. 315 mm 50.0.0 Steam cylinder, condenser cylinder and pump bodies are of glass: the valve gearing is also arranged under glass so that all processes can be observed when the engine is working. The engine has simple valve gearing, Watt's parallelogram, cold water pump for keeping the water in a reservoir at constant level, condenser, hot water pump for emptying the condenser, feed pump for the boiler, and flywheel. .Vi.L'77. Model Of a Thornycroft Boiler, Figure, entirely of copper, with manometer for '/•> atin., safety valve, and pipe union -40.0.0 In order to observe the process of boiling, the steam space is closed in on both front sides by wired Heating is effected by 4 Fletcher IIUIIH-I-. 55,278. Model of a Diirr Boiler, Figure, entirely of copper, with manometer for ' ., atin.. safety valve and pipe union With front sides of the steam space cln-ed by glass and Fletcher burner ten heatin.i;. (1. 8124, 1909, 1910 Steam Engines. 637 55 282. 1 : 6. 55 285. 1 : 7. 55 288. 1 : 3. ">, i'7!t. Sectional Model of Locomotive, F i g u i c, movable, with reversing gear 55.281. Locomotivo with valve gear, brass boiler, running in one direction only. Length 370 mm, height 230 nun, construction similar to Fig. 55,282 55.282. Locomotive, F i g u r e, with Reversing Gear, running backwards and forwards, with brass boiler, 2 safety valves, water gauge, whistle and cocks; for spirit fuel .... Dimensions: diain. of driving wheel 100 mm. Size of entire engine 520 x 180 x 370 mm. 55.283. Locomotive Chassis, Figure, with cylinder and valve-chest in section, same size as loco. Xo. 55,282 55.284. Piston Rod in oscillating cylinder 55.285. Watt's Governor, Figure . . Watt's Pendulum, Flywheel Governor and Throttle Valve: sec Nos. 51,982 and 51,983, p. 281, No. 55,253, p. 631 and 55,265, p. 633. 55.286. Parabolic Governor after Farcot 55.287. Ring Governor 55.288. Section Model of an Injector after Giffard, of bronze, Figure . . £ s. d. 1. 5.0 7. 0.0 15. 0. 0 12. 0. 0 7. 10. 0 6. 0.0 8. 15. 0 7.15.0 5. 0.0 Cl. 1911, 1910. 1912, 1904, 3692. 638 Propagation of Heat. Xn. .V. 289 — 55 289. 1 : 8. 55 291. 1 : 3. 55 292. 1 : 8. 55 294. 1 : 5. 55 290. 1 : 5. 55 293. 1 : 8. 55 295. 1 : 7. Propagation of Heat. 55,289. Apparatus for demonstrating Thermal Conduction in Metal Rods, after Ingenhouss, Figure (W. D., Fig. 379 [359]; Gan.-Eein., Fig. 390), with rods of copper, brass, zinc, tin, iron and lead, coated with silver mercury iodide The paint, having a beautiful yellow colour in the cold state, becomes brown when heated, resuming, however, its yellow colour some time after cooling. ">, 290. - - idem, with vertical Rules, Figure * 55. -Jill. - - idem, smaller, Figure, with 5 rods to which metal rings are stuck on with wax, for lantern projection (Fr. phys. Techn., I, 2, Fig. 3861) .......... 55,:_'92. Apparatus after Miihlenbein, with Bunsen Burner, Figure, with bars, arranged star-shape. of brass, zinc, tin, iron, German silver and wood, painted with silver mercury iodide; they ;m- heated from the centre (Fr. phys. Techn., I, 2, Fii,r. .'5*64) .... .V>.293. - - i d e in, with Spirit Burner, cf. Fig. 55,293 (Fr. phys. Techn., I, 2, Fig. 3865) . 55.294. Apparatus for showing the Conduction of Heat in Metal Rods, F i g u r e, after Rebens- torff, for steam heating (W. I)., p. 568 [527]; Ztschr. f. d. phys. u. ehein. I'.. 21. 1908, p. 297), with rods of copper, brass, zinc, tin, iron and lead, coated on one side with mercury copper iodide (red) and on the other witli mercury silver iodide (yellow) . . ."•."•.2 95. Apparatus for demonstrating the different Thermal Conductivity of Copper and Iron, Figure, coated with thermoscopic paint ................... 01. 6206. 1919, * Ciin lie used with the projection ;i)>|i;ini1 us. 1916, 1918, I s. d. i. o.o 1. 2.0 0. 12. 0 1. 10.0 1. 10. 0 1. I. U 0. 12. d 5887, 3693, 3691. No. • Thermal Conductivity. 639 55 301. 55 302. 1 : 5. * 55,296. Apparatus for demonstrating the different Thermal Conductivity of copper, lead and wood, for steam heating, Figure, arranged for the projection lantern (Fr. phys. Techn., I, 2, Fig. 3859) 55.297. Copper-Mercury Iodide, for experiments on thermal conduction and thermal radiation 50 grams 55.298. Rods of Copper, Brass, Iron, Glass, Wood and 12 small Lead Spheres, after Friedr. C. G. Miiller, for showing different thermal conductivities (M. T., p. 162) The spheres are attached to the rods by wax, the ends of the rods being then exposed to heat singly or together, and the pendulum beats being observed. 5."). 299. Thermal Conduction Apparatus after Looser, with air thermoscopes (Looser, Versuche aus der Warmelehre, 3rd Edn., p. 131 [2nd Edn., p. 113]; Fr. phys. Techn., I, 2, Fig. 3867), with 8 bars and octuple thermoseope 55,300. Apparatus after Wiedemann and Franz, Figure, for Thermal Conduction in Metal Rods, with 6 Rods (M. P., Ill, p. 775 [II, 2, p. 607]; Pogg. Ann. d. Physik u. Chemie, 3rd Series, Vol. 89, 1853, p. 501, and 4th Series, Vol. 95, 1855, p. 337) The 6 rods consist of iron, aluminium, zinc, tin, brass and German silver. The measurement is made in vacuo and in an air-filled space by means of a thermocouple. * 55,301. Gypsum Slab and Heating Rod, for showing the elliptical Propagation of Heat in Crystals, Figure (W. D., Fig. 380 [360]) The small gypsum slab coated with paraffin wax is provided with a hole into which is inserted a copper rod which can easily be heated by a flame. A pasteboard screen holds off any disturbing light. The apparatus is used with the horizontal projection apparatus. 55,302. Apparatus for explaining unequal Thermal Conduction in Crystals, after Senarmont, F i g u r e, with 4 pierced crystal plates, quartz ground parallel to axis, quartz perpen- dicular to axis, calc-spar perpendicular to axis, and gypsum (Fr. phys. Techn. I, 2, Fig. 3829) 55. .',03. Wood Pyramid with Brass Tube carried through, F i g u i- e, for showing the difference in thermal conduction in wood in a direction along the grain and across the grain (Ztschr. f. d. phys. u. chem. U., 21, 1908, p. 298) 55303. 1 : 8. £ s. d. 0. 14. 0 0. 5.6 0. 4.0 6. 0.0 15. 0.0 0. 5. 0 2. 8.0 0. 5.0 * Can be used with the projection apparatus Cl. 1923, 384-2, 368, 0131, 1709. 640 Propagation of Heat. No. ."..". :!04 — 55 311. 1 : 3 55 312. 1 55.304. Wood Cone for showing the Influence of Direction of Grain, after Eebenstorff £ Figure, with stand, boiling flask, rubber tubing and glass dish (Ztschr. f. d. phys. u. chem. TL, 21, 1908, p. 298) 0.16.0 55.305. Wire Gauze Cylinder, for demonstrating the safety lamp (M. T., pp. 162/3) ... 0. 1. 0 55.306. Davy's Safety Lamp (M. P., Ill, Fig. 457 [II, 2, Fig. 295]) 0. 8.0 55.307. Wolf's Safety Lamp, Figure, ignited from outside 0. is. n In practical use in most German coal-mines. 55.308. Apparatus after Despretz, for showing Decrease of Temperature with distance from Thermal Source (M. P., II, 2, Fig. 297), with 7 thermometers 3. 4. o 55.309. -- idem, with 5 thermometers, Figure 2. 1 1. 0 * 55,310. - - idem, with 3 thermometers 2. 8. 0 55.311. -- idem, smaller, for objective demonstration, with 3 thermometers, Figure, o. H'>. 0 55.312. Apparatus after Dcspict/.. for showing Decrease of Temperature with distance from Thermal Source (M. P., Ill, Fig. 459 [II, 2, Fig. 297]; (Ian. -.Man.. Fig. 535; Gan.-Kcin.. Fig. 391), the rod being heated by oil or water bath. Figure, with 7 thermometers 3.12.0 •V>.313. -- idem, with 5 thermometers 3. <>. 0 •V),314. -- idem, with 3 thermometers 2.14.0 55,315. Apparatus for investigating the Thermal Conduction of Liquids, Figure, gla>> eylim'er with differential thermosenpe and vessel for placing above this to contain the heated liquid (Gan.-Kein., Fig. 393) ; 1. o. () * Can !»• used with projection apparatus. ri. 1920. .-,"77. MUI. -' No. 53321. Thermal Conduction in Solids, Liquids and Gases. 641 * 1 55 315. 1 : 6. 55 316. 1 : 5. 55 317. 1 : 7. 5S318. 1 : 5. 55 320. 1 : 5. 55 321. 1 : 8. 55,316. Tube with Heating Bulb for Thermal Conduction and Convection in liquids, after Eebenstorff, Figure, for steam heating (Ztschr. f. d. phys. u. chem. U., 21, 1908, " p. 298) Two bushes made of thermoscopic paper are slipped on the glass tube. In the vertical position the difference between conduction and convection of the liquid in the tube is shown. 55,317. Apparatus for investigating the Thermal Conduction of Liquids, Figure, cylindrical glass vessel with steam capsule, on stand (W. D., Fig. 381 B [361 B]) 55,318. Apparatus for thermal Conduction of Gases, after Grove, Figure (M. P., Ill, Fig. 469 [II, 2, Fig. 306]) 55.319. 2 Glow Lamps after Grimsehl, one evacuated, the other filled with hydrogen, also 2 Chromothermoscope Screens, one backed with black paper and the other with tin- foil, for showing variation in thermal conduction and convection (Grimsehl: Die elek- trische Gliihlampe im Dienste des physikalischen Unterrichts, pp. 13 and 50) .... 55.320. Apparatus for thermal Conduction of Gases, after Magnus, Figure (M. P., Ill, Fig. 470 [II, 2, Fig. 307]) ........................... 55.321. --idem, Figure, fitted up more completely ............... £ S. d. 0. 6.0 0. 14. 0 0. 14. 0 0. 15. 0 1. 8.0 3. 0.0 Cl. 3423, 4148, 6203, 1926, 1927, 192S. 41 642 Thermal Conduction, etc. No. 55322 - 55 322. 1 : 3. 55 325, 55 326. 1 : 12. 55 326. 1 : 7. 55 323. 1 : 8. 53 078. 1 : 9. 53 077. 1 : 7. 55330. 1:10. 55,322. Apparatus for Thermal Conduction of Gases, after Weinhold, Figure (W. D., Fi£. 383 [363]) ................................ 55,323. Apparatus for Thermal Conduction and Convection in Gases, Figure, after Bebens- torff, on stand, tilting back on hinges, for steam heating (Ztschr. f. d. phys. u. chem. U., 21, 1908, p. 300) ....... ........ .............. The two comparison glass tubes are filled with, say, hydrogen and air. They are fitted with conical jackets of thermoscopic paper, wound round the heating tubes. The apparatus is used suc- cessively in a vertical and horizontal position. 53,078. Apparatus for demonstrating the Cooling Effect of Gases, Figure, after Tyndall (Tyndall, Warine [Heat], Fig. 83), with lateral flexible tube stopcock for introducing gases, and a cock for connecting up to the air pump, for placing on the air pump plate 55,325. Radiation Tube after Eebenstorff, F i g u r e, with 3 telescopic tube parts, a detachable radiation cone, a slide tube of pasteboard, blackened inside (Ztschr. f. d. phys. u. chem. U., 21, 1908, p. 303), can also be used for experiments on the propagation of air-impulses (Fr. phys. Techn., I, 2, Fig. 3709), price exclusive of thermal source or coloured leaves 55,320. Thermal Supply for Radiant Heat, after Rebenstorff, Figure, consisting of a Bunsen burner with slotted head and gauze rectangle (Ztschr. f. d. phys. u. chem. V., 21, 1908, p. 300) ........ £ s. d. 0. 8. 0 1.10.0 55,011. 10 Thermoscopic coloured Leaves after Eebenstorff 53,077. Apparatus after Davy, Figure, for Thermal Reflection in vacuo, receiver with two concave minors, thermometer and heating wire, for setting up on the air-pump (Gan.-Eein., Fig. 408) 53,750. Parabolic and Cylindrical Mirrors alter RebenstoilT, see Fig. 53,750, p. 476, for reflection experiments (Ztschr. f. d. phys. u. chem. I'., 21, 1908, p. 302) Cl. 1929, 4150, 5070, 4117,3884, ! 2. 0.0 d. 18.0 0. in. it 0. 4.0 3.3. 0 0.16. 0 4160, 6056. No. 55341. Thermal Conduction of Gases. Thermal Radiation. 643 55 338. 1 : 6. 55 331, 55 337. 1:12. 55341. 2:3. 55,328 55,329 55,330 55,331 55,332 200 250 300 400 500 95 75 120 125 160 1. 12. 0 2.0.0 2.8.0 3.0.0 4.4.0 Spherical Concave Mirrors, of Gorman Silver, cf. Fig. 55,330/1, special construction, arranged to rotate on firm iron stand, with adjustable Sponge or Bulb Holder, with protecting cover, without Table: List No. Diameter mm Focal Length mm Each £ The sponge and bulb holders are now fixed to the mirror mount instead of to the base, in the case of all mirrors from No. 55,328 to 55,332 (see Fig. 55,331). If the position of the mirror is changed the relative position of holder to mirror remains unaltered. The mirrors to 300 mm diam. are supplied with a hinged tripod stand, as Fig. 55,330, and the two larger ones with two trunnions on base frame as Fig. 55,331. Where a single mirror is ordered, a Sponge Holder will be supplied with same; if a pair of the same mirrors are ordered, a Sponge Holder and a Bulb Holder are supplied. Parabolic Concave Mirrors, of German Silver, cf . Figs. 55,330 and 55,331, of special construction, adjustable on firm Iron Stand, with adjustable Sponge Holder or Bulb Holder, with protecting cover, without Table: 55,334 300 50 2. 12. 0 55,335 390 70 3. 10. 0 55,336 500 70 5. 10. 0 1.10.0 List No. 55,333 Diameter mm 250 Focal Length mm 40 Each £ 2. 4. 0 Get-up: as Nos. 55,328 — 55,332. 55.337. Table for setting up Concave Mirrors, see Fig. 55,331, without mirror Glass Concave and Convex Mirrors: see Nos. 53,754 — 53,794, p. 477 and 478. 55.338. Thermometer on Stand, Figure, for setting up at the focus of the concave mirror, from 0° — 150° C ' 0. 10. 0 55.339. Iron Wire Mantle for glowing charcoal, with shank and stand (M. T., p. 163) . . 0. 10. 0 55.340. Platinum Cap (Gauze), with Bunsen Burner, cf. Fig. 55,341, for radiation experiments variable with the thermoscope. Price according to cost of platinum £ 1. 2. 0 to 1. 8. 0 55.341. Platinum Cap alone, Figure (W. D., Fig. 367 [347]), price according to cost of variable platinum £ 1. 0. 0 to 1. 6.0 54,950. Thermoscope after Weinhold, Fig. 54,950, p. 588 (W. D., Fig. 368 [348]) ..... 0. 3 Cl. 5056. 3421.1932, 41 » 644 Thermal Conduction, etc. No. 55 342 — 55 350 A (55 351, 55.352, 55 353, 55 354, 55 355, 55 356a, 55 358, 55 361). 1 : 8. 55 342. 1 : 2. 55 343. 1 : 2. 55 345. 3 : 10. 55 349. 1 : 4. £ s. d. 0. 1.9 * 55,342. Small Flat Flask for filling with Carbon Bisulphide and Iodine, Figure, for showing the Dark Kays (W. D., Fig. 370 [350]), without charging material, in sheet metal flask The small flask is supplied with a larger sheet iron flask in which it, is kept, after filling, pro- tected from light or fire. The flask cannot be delivered filled and is therefore provided with stopper. Filling must not be done near an open flame; even a glowing cigar should be avoided. * 55,343. Spherical Flask, Figure, working as Burning Glass for Dark Bays (W. D., Fig. 371 [351]), in mount, for filling with iodine and carbon bisulphide, with Tinder Holder, uncharged, in sheet iron bottle 0. 8. 0 With sunlight or an arc lamp the flask acts as a burning glass und ignites the tinder. Kindly observe the remarks to preceding item. 55,343 a. 1 Silvered and 1 blackened Glass Flask, for showing the dependence of absorption and emission of heat on the nature of the surface (M. T., p. 164) (). 0.0 Can be used with the projection apparatus. Cl. 1937, 1933. 1934.370, 1936. No. 55357. Radiant Heat. 645 55 350 B (55 362, 55 348, 55 365, 55 366), 55 369, 55 388. 1 : 8. 55,344. Thermometer in vacuo, after Rumford, for showing the rapid propagation of Radiant Heat through a vacuum (Gan.-Man., Fig. 537; Gan.-Rein., Fig. 400) * 55,345. Plane Parallel Vessel for alum solution, Figure, collapsible (W. D., Fig. 307 [290]) The vessel consists of two plane parallel glass slabs with a piece of rubber laid between # 55,346. - - idem, composed entirely of glass, 100 x 100 x 10 mm * 55,347. Device for Absorption of Heat Rays by Coloured Glasses The apparatus consists of a radiometer, a flat flask with concentrated alum solution and a number of coloured glasses in wood frames. 55.348. Apparatus for the Absorption of Heat Rays in Gases and Vapours (W. D., Fig. 372 [352]), a brass tube, closed at the ends with rock salt plates, on stand 55.349. Apparatus for showing that air is not heated by Thermal Rays, Figure (W. D., Fig. 373 [353]) A hollow brass cylinder is closed by two rock salt slabs 45 x 45 mm and 6 mm thick. 55.350. Melloni's Apparatus for Experiments on Radiation, Refraction, Absorption and Re- flection of Heat, Figs. A and B (M. P., 9th Edn., II, 1, Fig. 523; Gan.-Rein., Fig. 406, 411 — 414, 419), without thermopile or rock salt prism The apparatus comprises parts Nos. 55,351—55,355, 55,356 a, 55,357, 55,358, 55,348, 55,361—55,366 and 55,367. For preparations see Nos. 55,368 — 55,385. 55.351. The Stand, with a 2 m long rule, divided in cm, of maple and fixed to a baseboard by two pillars This stand as well as the following ones can be used simultaneously as an optical bench; also all apparatus fit the stands of optical benches 53,929 — 53,930, so that one frame only is necessary for the optical bench and Melloni Apparatus. 55.352. 8 Brass Stands, arranged for clamping to the rule Each £ 0. 5. 6 55.353. Locatelli Lamp, with square wick and reflector 55.354. Weinhold Steam Capsule, polished on one side and blackened on the other, 95 mm diameter . . . 55.355. Stage with Stand, Platinum Spiral and Spirit Lamp 55.356. Copper Screen, blackened, for use as constant thermal source (a) without stage or spirit lamp (b) with stage and spirit lamp 55,357. Platinum Cap No. 55,341 with Bunsen Burner and with shank for inserting in a stand No. 55,352 £ s. d. 1. 4.0 0.12.0 0. 5.0 0.16.0 1.12.0 2. 4.0 14.4.0 2. 0. 0 2. 4. 0 0. 16. 0 0. 10. 0 0. 18. 0 0. 8. 0 0. 18. 0 1. 6. 0 * Can be used witli the projection apparatus. Cl. 1938. 646 Thermal Conductivity, etc. No. 55358 — 1 * 55 364. 1 : 7. 55 359. 1 : 7. 55 386. 1 : 6. 55.358. Cube alter LesLe, 10 cm side, with 4 different surfaces, polished metal, dull white, dull black and £ shiny black, with Thermometer and Heating Box 0. 55.359. — idem, with 4 thermometers, divided in 1/5°, Figure 2. 55.360. Cube after Leslie, with 4 polished surfaces of different metals: brass, steel, zinc and iron I. ». ,1. 18. 0 4. 0 4. 0 16. 0 18. 0 8. 0 4 0 8. 0 10. (I 55.361. Double Screen, of sheet zinc, on hinge 0. 55.362. Screen with rotary disk, with holes of different diameter 0. 55,348 a. Brass Tube with Rock Salt Slabs, closed, without stand, Pig. 55,350 B, or 1. 55.364. Glass Tube, with brass mount, Figure, closed by rock salt slabs 3. 55.365. Holder for carrying Crystal and Gypsum Plates o 55.366. Rotary Bar with divided circle and adjustable stage 1. 55,388. Thermopile of 36 elements, arranged square, in mount with polished funnel 2. 14. 0 55.367. Stages for setting up Rock Salt Prisms and the like o. 4. 0 Galvanometer (Multiplier): see under "Electricity". Rock Salt Prisms. List No. 55,368 55,369 55,370 Side x Height mm 30x40 35x45 40x50 £ 1.0.0 1.4.0 1.8.0 Rock Salt Slabs. List No. Size mm £ 55,371 25x25 0.8.0 55,372 30x30 0. 10. 0 55,373 40x40 0. 18. 0 55,374 50x50 1.6.0 55.375. Plates of Alum, Borax, Sugar, Calc-spar, Agate, Crown and Flint Glass, Sal-ammoniac Each 55.376. Plates of Black Glass, Citric Acid and Mica Each 55.377. Quartz Plates, ground perpendicular or parallel to axis, of Heavy Spar, Fluorspar Each Rock Salt Cylindrical Lenses, radius of curvature 300 mm. List No. 55,378 55,379 55,380 55,381 Diameter mm 30 40 :><> «() £ 0.18.0 1.4.0 1.12.0 2.0.0 Rock Salt Lenses, bi-convex, 300 mm radius of curvature. List No. 55,382 55,383 55,384 55,385 Diameter mm 30 40 50 60 £ 0.14.0 1.0.0 1.8.0 1.18.0 55,386. Melloni Pile, linear, Figure, on stand with slider and graduation and with thernm- pilr No. .V>,392 0. 4. 0 0. 3. 0 0. 8. 0 12. 0. 0 Thermopiles, Figure, arranged square, in mount with polished reflector. List No. 55,387 55,388 55,389 55,390 Number of elements '-'•"> '•>*> I'.i r. | £ 2. 2. 0 2. 14. 0 3. 6. 0 4. 8. 0 Cl. 3425, 5123, 1939. No. 55 398. Radiant Heat. 647 55387—55390. 1:4. 55391 — 55394. 1:6. 55 395. 1 : 4. 55 397. 1 : 5. 55 398. 1 : 7. Thermopiles, Figure, arranged oblong, with mount, and gap opening symmetrically. List No. 55,391 55,392 55,393 55,394 Number of Elements 24 36 48 60 £ 2.14.0 3.6.0 4.4.0 5.0.0 55.395. Linear Thermopile after Eubens, Figure, consisting of 20 elements of iron and constantan, in mount, with German silver reflector polished inside, on adjustable stand (Ztsehr. fur Instrumentenkunde, 18, 1898, p. 64; Ztschr. f. d. phys. u. chem. U., 11, 1898, p. 126) 55.396. Tinfoil Screen, on Base, Fig. 55,010 A, p. 600 (W. D., Fig. 374 [354]), with silver- mercury iodide paint and black ring, for explaining Power of Absorption and Eeflection 55.397. Steam Capsule after Weinhold, for Radiation Experiments, Figure (W. D., Fig. 369 [349]), on stand 55.398. Apparatus after Eitchie, Figure, for showing the relation between Emissive and Absorptive Power (Gan.-Eein., Fig. 410) > . The apparatus, having the form of a differential thermometer, possesses two similar metallic air capsules and one of medium size intended 1<> he tilled with warm water. All capsules are white on one side and black on the other. £ s. d. 3. 14. 0 0. 8.0 0.12.0 2. 2.0 Cl. 1040, 1041, 1948, 1919. 1942, 648 Thermal Conduction, etc. . :)99 — 55 402. 1 : 5. 55 403. 1 : 6. 55.399. Thermal Radiation Apparatus after Bumford, consisting of 2 cylindrical vessels, one with smooth and the other with rough surface, for comparing surface radiation, with 2 thermometers divided in 1/2 degrees Both vessels are filled with boiling water and the time is measured which is required ;for cooling down to a definite temperature. 55.400. Thermal Radiation Apparatus after Dulong and Petit, consisting of a mercurial thermo- meter with large thermometer vessel and with holder and screens The thermometer is heated to a definite temperature and the time measured for the thermo- meter to cool down to the surrounding temperature. The experiment is repeated after covering the thermometer chamber with lamp black, leaf gold, leaf silver or with different dyes. 54,531. Gap with Micrometer Screw and Divided Drum, Fig. 54,531, p. 545 54,530. - - idem, without Micrometer Screw or Divided Drum, Fig. 54,530, p. 545 . . . 55,401. Surface Bolometer for measuring Badiant Heat, cf. Fig. 55,402, after Lurnmer and Kurlbaum, with two Branches and protecting box with slider (Ztschr. f. Instrumenten- kunde, 12, p. 81; Wied. Ann. 1892, Vol. 46, pp. 204 et seq.) The bolometer is based on the change in electrical conducting resistance produced by the heating, on radiation, of a lamp-blacked platinum grating of extreme fineness (0.001 mm thick) fixed to a small slate frame. The change in resistance is measured by means of the Wheatstone bridge combination. .">"•. 402. -- idem, with 4 Branches, Figure, with protecting box, sliders and central diaphragm 55.403. — idem, Figure, with 4 branches, two of which can be illuminated alternatively by lateral displacement of the apparatus (Physikalisch-Technische Beichsanstalt pattern) The detachable protecting box is provided with a pipe for the introduction of a thermometer. 55.404. Linear Bolometer after Lummer and Kurlbaum, Figs. A and B, with 2 branches, with mount In this apparatus the slate frame is provided with two fine platinum strips which are connected up as adjacent branches of the Wheatstone bridge and one of which is screened off from the rays. The apparatus is employed in conjunction with a spectrometer, this method of using being explained by F i K. .V>.404 B. v>.lor>. Capsule with Slate Frame, Fig. 55,404 A, for forming a 4-branch Bolometer I' rum the preceding apparatus Very sensitive galvanometers should be used for connecting with the bolometers (10~8 to 10-9 amp. sensitivity), see section "Electricity". Cl. 1945, 1946, 4104, 4543, £ s. d. 2. 0. 0 t •2. 8.0 1. 13. 0 1. 3.0 3. 0.0 4. 10. 0 5. 0.0 3. 0.0 ]. 6. 0 1951. No. 55418. Radiometers and Radiophones. 649 55 414. 1 : 2. 55 416. 1 : 8 55 418. 1 Radiometers and Radiophonic Apparatus. 55.406. Radiometer after Crookes, ordinary pattern 55.407. — idem, with two vanes rotating in opposite directions, Figure 55.408. - - with aluminium vanes, covered with mica one side 55.409. — with semi-cylindrical vanes (aluminium) . . . 55.410. - - with hemispherical aluminium vanes 55,411. Radiometer after Eebenstorff, Figure, with one vane having lengthened surface in order to enable the revolutions to be counted, with wood screen and two wire nets of nickel; also adapted for experiments on Absorption and Eeflection of radiant heat after Freuchen (Ztschr. f. d. phys. u. chem. U., 20, 1907, p. 28) 55,326. Heat Supply for Radiant Heat, for above, F i g. 55,326, p. 642 55,412. Radiometer with fixed metal disc (aluminium, copper) and rotary cross above same of transparent mica 55,413. - - i d e m, with fixed cross and rotating disc above * 55,414. Radiophone after Weinhold, Figure (W. D., Figs. 375 and 377 [355 and 357]), apparatus for producing a tone by rapidly repeated radiation, consisting of a plate glass sector disc for the whirling table, and the receiver * 55,415. - - i d o m, with a zinc sector disc (W. D., Fig. 376 [356]), fitting the whirling table 55,416. Electric Motor with Stand for driving the sector disc, Figure, without disc . . 55,417. 2 Lenses, bi-convex, 80 mm diam., 500 mm focal length, in mount, on stands for the preceding radiophones (W. D., Fig. 378 [358]) Price, together 55,418. Radiophone after Mercadier, Figure (M. P., 9th Edn., II, 2, Fig. 338), with 4 rows of holes giving a chord, keyboard, receiver and sound horn; without wMrling table . * Can be used with the projection apparatus. Cl. 5157, 1952, 1953, £ s. d. 0. 5.0 0.10.0 0. 6.0 0. 6.0 0. 6.0 0. 10. 0 0. 10. 0 0. 8.0 0. 8.0 0.18.0 0.14.0 2.14.0 1. 6.0 18. 0. 0 19531. 650 Meteorological Appa-atus. No. 55 420 - 55420. 1:|10. 55423. 1:11. 55 426. 1 : 4. 55 425. 1 : 5. 55 427. 1 : 6. Meteorological Apparatus. £ s. d. Chamber and Siphon Barometers, Staton and Travelling Barometers, Altitudinal Barometers and Aneroid Barometers: sec pp. 372—377, Nos. 52,771 — 52,806. Recording Aneroid and Mercurial Barometers: see p. 377, Nos. 52,8(18—52,810. Cathetometers: see pp. 224, Nos. 51,463 — 51,466. Reading Microscopes: see pp. 226 and 227, Nos. 51,473 — 51,477. Thermometers: sec pp. 576 — 579, 54.845 — 54,877. Thermographs: sec p. :,'<>. Xos. 54,878 — 54,885. Boiling and Freezing Point Determination Apparatus: see p. 580, Nos. 54.8H7 — 54,889. Thermometer Comparators and Calibrating Apparatus: see p. 225, Nos. 51,467 — 51,468. Distance Thermometers: sec pp. 584 — 587, Xos. 54,912 — 54,944. Thermometer Testing and Comparing Apparatus: see p. 581. 55,420. Thermometer Screen alter atephenson, Figure, with double blinds . for 4 or more thermometers, •Vi.lLM. Earth Thermometer after Lament, divided in ljb°, from — 10° to + 50" <'., for 0.25 in depth, in brass mount with steel point .V>. 122. -- idem, for 0.5 m depth ."..">. 123. -- idem, for 0,75 m depth, Figure .">.">, H'l. - - idem, for 1 m depth 55,425. Earth Minimum Thermometer, F i g u r e, very sensitive, spirit filled and with thermo- meter vessel in form of hollow cylinder Cl. 1968, 1971 4106, 197-2, 2.10.0 0. 18.0 1. 2. I" 1. 4.0 l. Ki.o 1. 0.0 3829. No. 55 438. Thermometers. Recording Instruments. Actinometers. 651 55 437. 1 : 5. 55438. 1:10. £ s. d. 55.426. Spring Thermometer, Figure 0. 10. 0 The maximum system thermometer is divided iu 1/6° from — 10" to + 100" C. and has a pro- tecting ring for the mercury bulb, the latter being provided with a tuft of hair for holding the spring water. 55.427. Baro-Thermograph, Figure, combined recording instrument for air-pressure and temperature, in walnut case 12. 10. 0 55.428. --idem, in aluminium casing 15. 0. 0 55.429. Baro-Hygrograph, in walnut case 13. 0. 0 55.430. Baro-Psychograph 15. 0. 0 55.431. Thermo-Hygrograph 12. 10. 0 55.432. Baro-Hygro-Thermograph 18. 0. 0 All recording instruments are also supplied in a metal casing at the same price. 55, -133. Statoscope for observing the ascent and descent of a balloon, model of the Eoyal Aeronautical Batallion 4. 10. 0 55.434. Aneroid Barograph, one rotation of drum in 12 hours, with leather case, straps and rifle hook 7. 10. 0 55.435. Solar Radiation Thermometer, Figure, on stand 1. 4. 0 The mercury vessel is surrounded by an evacuated bulb; the thermometer is provided with maximum device, being graduated fiom — 10° to + 70° C. in l/z°- 55.436. - - Two of the preceding, without stand, in case 1. 16. 0 The bulb of one thermometer is blackened, the other plain. 55.437. Pair of Bulbs after Violle, Figure, for measuring solar 'radiation 4. 0. 0 Of the two bulbs, consist ing <>f thin sheet copper, one is dull black on the outside, the other polished and gilded; both bulbs are jet black internally. Each carries a thermometer divided in 1/t". 55.438. Actinometer after Violle, Figure, recording, with two scribing levers writing on drums .31. 10. 0 Two thermometers are, together with their sensitive vessels, enclosed in metal spheres, one of the latter being polished and the other jet black. Cl. 1973, 1974.3429. 652 Meteorological Apparatus. No. 55 439 - 55 441 B. 1:8. 55 439. 1 : 5. 55 441 A. 1 : 7. 55 443. 1 : 6. 55 444. 1 : 8. 55 446. 1 : 10. 55.439. Pyrheliometer after Pouillet, Figure, for showing the total amount of solar heat i £ s. d. absorbed by the earth (M. P., Ill, Fig. 473 [II, 2, Fig. 340]; Gan.-Eein., Fig. 453) . 4.10.0 55.440. Sunshine Recorder after Campbell-Stokes, for automatically recording the duration of sunshine, with adjustable polar altitude, centering device and sensitive sheets for one year's records 54,888. Hypsometer after Wollaston, see Fig. 54,888, p. 580, with one thermometer No. 54,874a 55.441. Hypsometer after Geissler, Figs. A and B, for altitudinal determinations from the boiling point of water by means of thermometers, with lamp and boiler, in box . . The thermometer is divided in 1/,0° from + 95 to + 102° C. 55.442. — idem, with large thermometer divided in 1/50° C 55.443. Hygrometer after Daniell, Figure (M. P., 9th Edn., II, 2, Fig. 352; W. u. E. phys. Prakt,, Fig. 102; Gan.-Man., Fig. 522; Gan.-Eein., Fig. 386) 9. 0.0 4. 3.0 3. 5.0 5. 0.0 0. 15. 0 55.444. Hygrometer after Dobereiner-Ke'gnault, Figure (W. u. E. phys. Prakt., Fig. 103; Gan.-Eein.. Fig. 387), with two polished silver vessels and two thermometers divided m Vio°> on brass stand, without aspirator 2. 10. 0 55.445. - - idem, with simple aspirator of 5 litres capacity (M. P., Ill, Fig. 480 [II, '2, Fig. 353]) 3.10.0 v> (10. Hygrometer after Be"gnault, Figure, with polished silver vessel for the ether, with extra-sensitive thermometer, in box s 4. 0. 0 55,447. Hygrometer after Alluard, Figure, with accessories (Gan.-Man., Fig. 523) . 4.16.0 Cl. 1976, 1977, 1978, 1979, 1980, 1982. No. 55 451. Actinometers. Hypsometers. Hygrometers. 653 55 449. 1 : 4. 55 451. 1 : 3. 55 453. 1 : 55.448. Capillary Hygrometer after Saussure. Figure (M. P., Ill, Fig 481 [II, 2, Fig. 357]; £ s. d. Gan.-Man., Fig. 520; Gan.-Eein., Fig. 389), with thermometer 1. 5. 0 55.449. Capillary Hygrometer after Koppe, Figure, with adjusting device and with thermometer 1. 16. 0 55 450. Hygrometer after Mithof, scale diam. 80 mm, in black polished wood mount ... 0. 4. 0 55.451. --idem, on base, Figure 0. 8. 0 55.452. - - idem, with rain shade and arm for fixing to window 1.5.0 55.453. Polymeter after Lambrecbt, Figure, in brass case (M. T., p. 161 and 162) . . 1. 0. 0 55.454. -- idem, in phosphor-bronze case (non-oxidisable) . . . • . 1. 5. 0 Cl. 1983, 1984, 1985, 1980. 1988. 654 Meteorological Apparatus. No. 55 4.i,"> — 55 455. 1 : 5 55 458. 1 : 7. 55456. 1 : 18 55 457. 1 : 6. 55.455. Weather Telegraph after Lambrecht, Figure, with barometer, thermometer and hygrometer The place at which the observations are to be conducted should be mentioned when ordering, as also height above sea-level. 55.456. Compression Hygrometer after Kolosy, Figure, with millimetre scale, for exact measurements of the humidity-content of the atmosphere, with thermometer in 1/8° C., for — 20° to + 40° C . This new hygrometer is based on the measurement of the tensive force of the moisture contained in the air at the time of the observation. The quantity of moisture is given in accordance With Dalton's law of partial pressures, being read off direct in whole percents and ' ,„ of a per cent. A fresh filling is rc(|iiired for each measurement. Directions for use and a Table for facilitating measurements are supplied with the apparatus. The relative humidity is determined by direct measurement, and the instrument can be used for calibrating and determining the constants of other hygrometers. ."..">. I. "i 7. Recording Hygrometer, Figure, with clockwork cylinder, making one turn every week; very accurate movement 55.458. Psychrometer after August, Figure, with two accurate thermometers in Vio° from --15° to + 50° C., with wood stand (M. T., p. 101) 55.459. -- idem, with metal stand 1. Cl. 6558, 621i, 4706, 5208. s. (1. it. (i 8.0 1(1. (t No. 55 464. Hygrometers. Psy chrome ters. 655 55 462. 1 : 5. 55 463. 1 : 4. 55 464. 1 : 4. 55,460. Psychrometer, simple, with large water vessel and two thermometers divided in 1/2°, j £ s. d. with Table 0. 10. 0 55;461. --idem, Figure, with lacquered zinc case for protection from weather . . . 55.462. Centrifugal Psychrometer after Schubert (Ztschr. f. Instrumentenkunde, 16, 1896, p. 329), Figure, with wood handle arranged for swinging, giving very rapid and accurate results, with two thermometers divided in 1/10° C In order to calculate the results, it is desirable to employ the Psychrometer Tables by J e 1 i n e k, II a n n and P e r n t e r, to be obtained from any bookseller. 55.463. Aspiration Psychrometer after Lambrecht, Figure, with two sensitive, tested thermometers, with hand motor 55,464. Aspiration Psychrograph after Lambrecht, Figure, with two sensitive, tested thermometers, with hand motor The apparatus differs from the preceding in that the thermometers are provided with marks, which follow the temperature variations during aspiration and fix the difference in the two thermo- meters after aspiration has ceased, so as to enable it to be read closely and carefully, with a magnifier if necessary. C). 1902, 1993, 1994, 1995. 0.15.0 2. 8.0 5. 0.0 5. 10. 0 656 Meteorological Apparatus. No. 55 465 — 55465. 1:0. 55 466. 1 : 5. 55 467. 1 : 3. 55 468. 1 : 7. 55 469. 1 : 7. 55.465. Direct Reading] Psychrometer after Lowe, giving relative humidity, dew-point, and water vapour tension. Can be used without Table In order to make a reading, the index knob is moved up or down until the upper index gives the same value on the temperature scale to the left as the dry-bulb thermometer to the right. The index knob is then turned, without being moved, until the lower index gives the temperature-value of the wet-bulb thermometer. The point at which the tip of the indicator is situated gives simultaneously the relative humidity, dew-point, and the tension of water-vapour. 55.466. Recording Psychrometer, Figure, with 7-day clockwork movement making one rotation in this time, with two thermometers and two levers, writing on a drum . . 55.467. Air Tester after Wolpert, Figure, for determining the amount of carbonic acid in the air in rooms; specially recommended for schools. Accurate determinations in a short time. With the necessary reagents in bottles £ s. d. 2. 10. 0 55.468. Rain Gauge, Figure, 125 sq. cm surface, with cylindrical measure 55.469. --idem, Figure, larger, 250 sq. cm surface V>.17<>. Rain Gauge after Bruhns, Figure, 500 sq. cm surface, with cylindrical measure and 2 rods with branded marks (Ztschr. f. Instrk., 8, 1888, p. 208) 55,471. Rain Gauge, ef. Fig. 55,472, consisting of graduated glass jar, brass cock, white enamelled lead funnel and arbor screw, indicating to 10 mm rainfall 55,471'. -- idem, larger, Figure, indicating up to 15 mm rainfall Cl. 6219, 1997, 1998, 1999, 9. 0.0 0. 12. 0 1 . 10. 0 •2. 10. 0 '2. M. «' 0. 5.0 0. 6.0 2000. No. 5547S. Psychrometers, Rain Gauges. 657 HejRimnur Pref Helliut" ~3 55 473. 1 : 8. 55 474. 1 : 20. 55 475. 1 : 7. 56.473. Rain Gauge after Prof. Hellmann, for catchment area of 100 sq. cm; the measuring j £ s. d. glass gives the rainfall in millimetres 55.474. Recording Rain Gauge, Figure, working very reliably, 8-day mechanism, on iron base, with reservoir and test vessel . . . 55,475. Recording Rain Gauge, Figure The catchment vessel is separate from the recording mechanism, in order to be able to set up the latter in the observing room and the former in the open air. 0. 9.0 27. 10. 0 12. 10. 0 Cl. 2001,4612, 3430. 4952, 2003. 658 Meteorological Apparatus. No. 5S478 - 55478. 2:3. 55 482. 1 55.476. Recording Water Gauge, F i g u i e, in glazed iron house, lower and front plate mo\ ing in hinges, with copper float on 2 m long rods and the necessary leads for snme . . 55.477. Wind Vane after Wild, Figure, with scale of forces 55.478. Anemometer after Robinson, Figure, counting to 10000000 metres, in case 55,470. -- idem, counting up to 10000 metres, Figure. . . . . . . . . 55.480. - - id em, counting to loo metres 55.481. -- idem, counting to 10000 metres, large pattern, working from 1 metres p.-r minute; diameter of protecting ring about IfiO mm .V..IS2. Anemometer after Becklcy, Figure, with counting mechanism and Robinson crossed cups 52,056. Apparatus alter Rosenberg. F i g u re, for Explaining the Theory of Cyclones, Anti- cyclones, Trade Winds and Counter Trade Winds (Ztschr. f. d. plus. u. chem. t'., 12, pp. 335—338) Tilt- apparatus is used in conjunction with a Whirling Table (see No. .M.'.»4!l cl scq.): the above price is exclusive ot the I'ltlcr. Accurate description and instructions tor use of the apparatus sent on application. 55,484. Apparatus for producing Smoke Eddies, Figu re. after Rosenberg, for Explaining the Existence of Cyclones and Ant i-cvclones (/tschr. f. d. phys. u. chem. I'., 12, IS'.t'.l. p. 338) ' '. ' The nhis> cylinder, open at both ends, can be detached from the wood base. The hitter carries Cl. 2017,6559, ' 2005. 2^07. £ s. il 23. 0.0 3. 0.0 5. 0.0 3.10.0 2.10.0 6. 10. 0 4. 10. 0 4. 10. 0 1. 4.0 No. 55 486. Water Gauge. Wind. Eddies. Storms. 659 52 056, 51 949. 1 : 9. 55 484. 1 : 8. 55 485. 1 : 10. 55 486. 1 : 10. a small metal plate on which German tinder or the like is allowed to burn in order to fill the cylinder with smoke. Air is then blown by means of a bellow through the upper pipe, cyclonic smoke eddies thereupon ensuing. 55,485. Eddy Apparatus after Collation, Figure, for producing eddies in a mass of water similar to atmospheric eddy winds (Comptes Bendus, April, 1887) 55,480. Storm Recorder after P. J. Schreiber, Figure This apparatus automatically shows storms within a radius of 20 km and records them on a paper disc connected to a 24-hour clockwork arrangement. To the apparatus pertain the coherer, together with shaking device, built into a well-closing chamber (the coherer, etc. serving1 simultaneously as an acoustic indicator); a sensitive relay and shunt resistance for a cell, together ivith ink writer in a separate glass ca»r. and three dry cells. In spite of its simplicity, the apparatus is very sensitive. The determination of the time of the individual electrical discharges can be carried out with accuracy, as the pen describes a distance of 10 to 12 metres in 24 hours. Complete description is appended to the apparatus. £ s. d. 6. 0. 0 9. 0. 0 Cl. 66tf, 3434, 5085,2012. 42* 660 Meteorology. Cosmology. No. 55487 - 55 491. 1 : 7. 55493. 1:8. 55492. 10. 55,487. 6 Meteorological Charts, mounted on linen, with rods for rolling up: (1) Isotherms for the mean annual temperature of the earth; (2) Isotherms for the mean .July tem- perature of the earth; (3) Isobars and Winds predominant in January; (4) idem in July; (5) Isanormals of temperature for January; (6) idem for July Cosmology. 55,488. Terrestrial Globe, Figure, on wood base, with nickelled meridian circle, oblique, 33 cm diameter 55.489. -- idem, on tripod, with compass, 40 cm diameter 55.490. - - i d e i n tripod with compass, 48 em diameter We quote on application for every kind of Globe for the teaching of Political and Physical Geography, Geology and Cosmology, such as Terrestrial Globes in relief, Geological Earth Globes, Lunar Globes in relief, Terrestrial Globes, etc. Cl. 3690, 2015, 3435, 2016. il s. tl. 1. 8.0 1. 4. (l •J. 4. 0 3. 10. 0 No. 55 497. Cosmology. 661 55 495. 1 = 9. 55 496. 1 : 8. 55497. 1:6. 55,491. Apparatus for Demonstrating Equinoctial Precession 55,492. Horizon after Bath, Fig are This apparatus permits of explaining the terms: "Plane, Horizon, Dead Level, East, West, North and South Points, East-West Line, North-South Line, Diurnal Circle, Diurnal and Nocturnal Arc, Point of Sunrise and Sunset, Eastern and Western Amplitude, Point of Culmination, Equator, Tropics, Sun's Altitude on the meridian and Altitude of the Pole", and answers the questions: When and how far does the sun set or rise from the Eastern and Western points? How large is the diurnal or nocturnal arc? At what altitude is the Sun (angle of the horizontal surface)? What is the inclination of the horizontal surface to the earth's axis (polar altitude)? These questions can be put for any part of the Northern Hemisphere and for any day of the year. 55,493. Apparatus for Explaining Ebb and Flow, after Archenhold, Figure A large white sphere represents the solid interior of the earth which is supposed to be com- pletely surrounded by water. The aqueous masses are represented by a white wire frame and a small sphere, representing the moon, is connected with springs to the earth's core. If the lunar sphere is taken away from the earth the aqueous masses (as in the case of ebb and flow) are changed from the spherical shape, and the tidal wave is shewn on the side turned towards and away from the moon: this tidal wave being smaller on the side turned away from the moon, corresponding to the greater distance from the latter. The earth can be rotated thus rendering the change from ebb and flow every six hours plainly visible. The action of the solar flow, amounting to about 2/6ths of the lunar flow, can be represented for the case of new and full moon by drawing away the lunar sphere to a greater extent, and for the case of the first and last quarters by drawing it away to a lesser extent. 55,495. Celestial Globe after Haller, Figure, with movable socket, adjusted for one degree of latitude . 4. 0. 0 When ordering it should be stated for which degree of latitude the apparatus is intended. The globe can be set for any month, day or hour. The invisible part of the heavens is con- cealed by the socket. The apparatus is applicable for shewing the stars of the firmament visible at any time and also for solving a few astronomical problems, e. g., determining the rising and setting and the highest position of the stars. 55,496. --idem, Figure, with fixed socket and movable globe; can be set for any degree of latitude By arranging the globe to be movable the apparatus, in addition to being used for the purposes mentioned, can also be employed for demonstrating the apparent rotation of the heavens during twenty-four hours by observing the same from any position on the earth. 55,497. Uranotrope after Dr. Wislicenus, Figure £ s. d. 1.16.0 4. 16. 0 4. 4.0 The Uranotrope serves for demonstrating the apparent rotation of the heavens and the apparent motions of the stars. It is formed essentially of a hollow brass sphere of about 20 cm diameter capable of rotation about an axis passing through it, in the centre of which axis placed a small terrestrial globe. This glass sphere represents the apparent terrestrial sphere, the terrestrial equator, the ecliptic, the tropic and polar circle, also the coloures of the equinoxes and solstices being etched on and painted in different colours Other entries should be made by the students during instruction by means of a coloured pencil supplied, with ink, or by pasting small paper pieces on the globe; the paper can be removed by washing off. — Complete description and instructions for use are appended to the ap- paratus. 01. 53131, 6228, 3811. 7. 10. 0 2. 4.0 662 Cosmology. No. 55498-55504. 55499. 55 504. 1 : 2. 55,498. Mang's collapsible Horizontarium; can be used at same time for demonstrating tlic £ s- d. apparent motion of tlie stars for any point of the earth. With directions and box . j 2.10.0 55.499. Mang's collapsible Armillary Sphere, F i g n r e, consisting of tlie preceding Hori- zontarium with a simple terrestrial sphere; with directions and box 55.500. Mang's collapsible Telurion-Lunarion, shewing the actual motions, proof of sphericity, oblate ring, existence of day and night, time, the degree in perpendicular axial position; with a powerful lamp, sliding concave mirror, directions and box 55,501. Extra Globe with water and land 55,502. Mang's collapsible Universal Apparatus for Astronomical Geography, containing a Horizontarium, an Armillary Sphere, Tellurion with Lunarion, a Planetarium; com- prises all motions of the celestical bodies, enables demonstration of the lunar epicycloid, demonstration of the precession, migration of the apparent lunar orbit, parallax of the fixed stars, etc.; on stand with instructions * :>.~>,r><>3. Rotary Star Chart of the Northern altitudes, Figure, for the latitude of Leipzig, with a disc having network of degrees and a disc without network; arranged for the Projection Lantern For demonstrating the motion of the circumpolar stars. The firmament can he set for any hour of tlie day. It is jiossihle with the chart to solve the problems of the rising and settini; of the stars and their culminations. #.">.">,."> I) I. Universal Clock, Figure, for explaining the times in different parts of the world, with the times of the most important towns noted, for objective projection; with rntai-v disc 4. 0. 0 2.10.0 0. 8.0 16.10.0 2. 0.0 1. 8.0 X- * Can lie used with the Projection apparatus. Cl. 410, 309.'), 409. Price List ho. 50, Vols. II and III. Physical Apparatus -IC8I- VOL. III. Magnetism, Electricity, Radioactivity, Miscellanea. Kolbe School Rheostat. MAX KOHL A. G CHEMNITZ (GERMANY) Adorfer Strasse 20. Telegraphic Adress: Physik. ABC-Code 5tn Ed. used. Fully paid-up Share Capital: £ 80,000. L. 50, Hie. Reproduction or imitation of Blocks strictly prohibited. C1. 5179,5180. Pages 663 — 784 have been omitted. Pages 1201 — 1240 are bound in with Vol. I (Equipements, Switchboards and Projectors). No. 60001-60025. Magnetism. 785 60 005. 1 : 6. 60 001 60 004. 1 : 2. 60 016. 1 : 5. Magnetism. Lodestone, stone in iron mount, Figure. List No. 60,001 60,002 60,003 60,004 According to size and beauty £ 0. 12. 0 0. 15. 0 0. 18. 0 1. 4. 0 60,005. 2 Bar Magnets and 2 Horse Shoe Magnets, Figure, with soft iron keeper, inserted in wood block Bar Magnets, of tungsten steel, round section, thoroughly magnetic, as per German designation. North pole lacquered red, South pole blue. List No. 60,006 60,007 60,008 60,009 Length mm 100 150 200 250 Diameter mm 8 10 10 14 £ 0.1.6 0.2.0 0.2.6 0.3.0 Bar Magnets, tungsten steel, of rectangular section and thoroughly magnetic. North pole lacquered red, South pole blue. List No. 60,010 60,011 60,012 60,013 60,014 Length mm 100 150 200 250 300 £ 0.1.10 0.2.0 0.2.6 0.3.0 0.4.0 2 Bar Magnets, Figure, best construction, rectangular section, with keepers and hanging lug, in case. List No. 60,015 60,016 60,017 Length mm 150 200 300 £ 0. 10. 0 0. 12. 0 0. 15. 0 60,018. 2 Bar Magnets, 100x10x6 mm, one of them being provided with a cap and with divided brass rail, for use with the Miiller Dynmeter in case, with keepers (M. T., pp. 212 and 220), and with tapered stand Horse Shoe Magnet, excellently magnetic, with keeper. List No. 60,019 Length of limb mm 100 £ 0. 2. 6 Horse Shoe Magnet, with 3 segments. List No. 60,023 Length of limb mm 150 £ 0.18.0 teeper. 60,020 60,021 60,022 150 200 250 0.3.6 0.4.6 0.6.0 60.024 60,025 200 250 1.2.0 1.6.0 £ s. d. 0.12.0 0.12.0 CL 2019, 2018, 2020. 50 786 Magnetism. No. 80 60 036. 1 : 4. 60 027. 1 : 5. 60 034. 1 : 7. 60 039. 1 : 3. 60043,60058. 1:5. 60 059. Horse Shoe Magnets, with 5 segments, Figure. List No. 60,026 Length of limb mm 150 £ 1. 4. 0 Horse Shoe Magnet, with 7 segments. List No. 60,029 Length of limb mm 150 £ 1.10.0 60,027 200 1. 10. 0 60,030 200 1. 16. 0 60,028 250 1. 16. 0 60,031 250 2.5.0 Laminated Magnet (Jamin's), Figure (Gan.-Man., Fig. 599). Length of limb, mm No. of laminae Barrying capacity, kg 60.032. 170 20 12 . . 60.033. 210 20 17 60.034. 300 20 20 60.035. 400 35 70 Magnetic Magazine, Coulomb's, Figure (M. P. 10th edn., IV, 1, Fig. 9; 9th edn., Ill, Fig. 21; Gan.-Man., Fig. 596; Gan.-Eein., Fig. 684). List No. 60,036 60,037 60,038 With 369 rods £ 1.4.0 1.10.0 2.5.0 60.039. 12 Steel Rings for magnetizing, Figure, only appearing magnetic after being cut, as suggested by Friedr. C. G. Miiller (M. T., p. 214) 60.040. 1 Piece Thin Sheet Steel, for cutting up for magnetic tests (M. T., p. 213). . . . Magnetic Needle, Rhombic form, with agate cap, Figure, without the stand illustrated. List No. 60,041 60,042 60,043 60,044 60,045 60,046 60,047 60,048 60,049 60,050 Length mm 30 50 60 70 80 100 120 150 £ 0. 1. 3 0. 1. 6 0. 1. 10 0. 2. 1 0. 2. 5 0. 3. 0 0. 3. 10 0. 4. 6 200 LT.O 0.5.6 0.6.6 Compass Needle, with agate cap, best construction. List No. 60,051 60,052 60,053 60,054 60,055 Length mm 80 100 120 l.~>o L'OO £ 0. 3. 0 0. 4. 0 0. 5. 0 0. 6. 6 0. 8. 0 60,056 250 0. 10. 0 60,057 300 0. 13. 0 60,058. Stand for Magnetic Needles, serpentine base, brass column and point, Figure ((Ian. -Man., Fig. 577), without magnetic needle illustrated tin. O.V.i. Test Needle in glass cylinder, Figure (M. P. 10th edn., IV, 1, Fig. 10) . . . . Astatic Magnetic Needle, with stand (Gan.-Man., Fig. 612). List No. 60,060 60,061 Length mm 60 loo £ 0. 9. 0 • 0.10. 0 s. d. 1. 15. U 2. 5.0 3. 0.0 6. 0.0 0. 1 . li 0. 0.6 (i. '_'. (i (I. 10.0 . 2023, yi'2\. L'"22. 4143,5587,5622. Xo. 60068. Fundamental Magnetic Experiments. 787 60 063. 1 : 5. 60 065. 1 = 6. 60 064. 1 : 6. 60 067. 1 : 6. £ s. a. 60,062. Astatic Magnetic Needle, Tremery's, with stand 0. 10. 0 This needle consists of two magnets, whose similar poles are turned outwards, the other poles being fastened to a piece of ebonite provided with a lug. The needle is thoroughly astatic. 60,06.3. Apparatus for explaining the Fundamental Laws of Magnetism, Figure: magnetic needle on stand, compass, simple dipping needle, bar magnet, steel bars for breaking, iron filings in box, with sieve and slab for sprinkling the same 1. 2. 0 60,064. Apparatus for Magnetic Experiments; can also be used as a dip circle 5. 10. 0 1 stand with brass base, 1 rotary needle holder, 1 needle holder for needles with caps, 1 com- pass card, 1 graduated circle, 4 various magnetic needles, 1 magnetic and 1 non-magnetic iron rod, with case. 60 065. Collection of apparatus for the fundamental experiments in magnetism, frictional contact and thermo-electricity, in wood box, Figure 2. 6. 0 The box contains: 2 magnet bars, 1 doublo hook for suspending these, 1 magnetic needle, 1 ebonite rod, 1 glass rod, 1 rubbsr, 1 insulating stand, 1 elestric needle, pithballs with holder, 1 glass rod with brass cap, 1 ebonite rod with brass cap, 1 Voltais coll with closing bow and one thermo-electric rectangle. 60.066. Cylindrical Nickel Piece, for magnetic experiments 0. 2. 0 60.067. Magnetic Double Pendulum, Figure 0. 5. 0 Two pieses of soft iron are su?p3nded vertisally from two threads on a stand. On approaching one pole of a powerful magnet the iron pieie? are attrasted, at the same time repelling each other smartly. 60.068. Iron and Steel Bars, for magnetic distribution, 6 of soft iron, 6 of hardened steel, 6 mm thick, 20 mm long . . . 0. 3. 0 Cl. 3450, 5555, 4114, 2021. 50* 788 Magnetism. "169 — 60 069. 1 : 4. 60 071. 1 = 5. 60 073. 1 : 6. 60 075. 1 : 8. 60 074. 1 : 4. 60.069. 12 Round Soft Iron Bars, 15 mm thick, Figure, two 150 mm and ten 20 mm long £ * d. (M. P. 10th edn., IV, 1, Figs. 4 and 5; 9th edn., Ill, Figs. 6 and 7; Gan.-Man., Fig. 585;: Gan.-Eein., Fig. 677) 0. :.". r> 60.070. 12 Tempered Steel Wires, for magnetising and breaking up 0. L'. o 60.071. Molecular Magnet Model, Figure, consisting of 24 small magnets, 20 mm long, moving on points 1. 4. o l». 0 The apparatus consists of a wood frame with a mica disc, the points carrying the magnets being fixed to this frame. The phenomenon is in this manner rendered plainly visible. .. k« »1 60.073. Molecular Magnet Model, Figure, consisting of 16 small magnets, 20 mm long, moving on points, each on separate base, on one baseboard 1. o. o 60.074. Molecular Magnet Model, von Beetz's, Figure, consisting of 8 magnetic needles tinning about the horizontal axis with red and white discs visible at a distance, for experimentally proving Ampere's hypothesis 1.14.0 60.075. Apparatus for determining the distribution of Magnetism in a bar magnet by measuring its carrying power, Figure (W. and E. Phys. Prakt., Fig. 360), with 2 magnets, 1 normal and 1 with consequent poles • 2. 5. 0 The carrying capacity is determined at the individual points of the bar magnet by the spring tension (proportional to the extension of spring), which suffices to pull the small iron ball from the magnetic body. i;o.o7(i. One Set Cardboard Sheets with magnetized sheet steel strips, F i g u r e, as suggested by Friedr. ('. (',. Miiller (M. T., Fig. 148), for demonstrating the path of the lines of force in simple and compound fields 0. 1*. 0 60,077. Cardboard Sheet with magnetic bars placed perpendicularly to same, Figure, for demonstrating the path of the lines of force of simple and compound fields in a plane perpendicular to the longitudinal axis of the bar magnets, as suggested by Friedr. C. G. Miiller (M. T., Fig. 14«t) 0. 5. 0 CI. 2025, S71, 5503. LML'-.I. W88. No. lit) 085. Molecular Theory, Lines of Force Theory. 789 60084. 1:21. 60 076. 1 : 6. u 60 078. 1 : 8. 60 079. 1 : 8. 60 085. 1 : 6. 60.078. Horse Shoe Magnet, of sheet steel, Figure, for demonstrating an approximately homogeneous field (Grimsehl, p. 648) 60.079. 2 Small Magnets, 1 horseshoe and 1 bar magnet, Figure, cemented to glass slabs, for objectively demonstrating the magnetic lines of force Apparatus for explaining the theory of the lines of force (Berghoff's), see Electricity Section. 60.080. Glass Tube, half filled with iron filings, and with closed ends, for explaining the exci- tation of magnetism 60.081. Iron Filings, strained per 250 g 60.082. Iron Powder (Limatura Ferri alcoholisata) '. per 250 g 60.083. Sifter for above 60.084. Soft Iron Rod for magnetic experiments, Figure (Friedr. C. G. Miiller's), 1.5 m long, 2 cm thick (M. T., p. 218) 60.085. Apparatus for explaining declination and inclination, as suggested by Prof. Zahl- bruckner, Figure (Fr. phys. Techn. II, 1, Fig. 566) The tripod with pillar carries a short arm, on which is fastened a globe and a rotary meridian arc. Inside the globe is a straight vertical electro-magnet, whose field corresponds to that of terrestrial magnetism. The conducting wires for the magnetising coil pass through the hollow axis and end in two terminals fitted to the stand. A slider is fixed to the arc of meridian with a magnetic needle, which serves as the inclinator and declinator. By adjusting the slider and turning the arc of meridian the needle can be turned in any vertical or horizontal plane. The globe is therefore fixed on the horizontal arm and the inclinator can consequently be brought to the lower magnet pole, which corre- sponds to the South pole of the earth. With the exception of the core of the electro-magnet and the magnetic needle the entire appa- ratus is free from iron. £ s. d. 0. 15.0 0. 5.0 0. 1.6 0. 1.0 0. 1.9 0. 1.6 0. 5.0 8. 0.0 Cl. 4178, 4177, 4176, 4192, 414-1. 5580, 5586, 5587, 2030. 790 Magnetism. \,,. I'.ll UVIi — 60 088. 1 : 3. 60 086. 1 : 5. 60089. 1:3. 60094. 1:2. 60 091. 1 : 4. 60092. 1:7. 60 093. 1 : 7. r 60 095. 1 : 3. 60.086. Apparatus for Explaining the Varying Magnitude of Inclination on the Earth, Figure (Fr. phys. Techn. II, 1, Fig. 567) ....... ................. The apparatus consists of a semi-circular magnet, which can turn about a circle in a stand, and a dipping needle placed above it. According to the position of the magnet relatively to the needle the latter shews none or different inclination. 60.087. Declination Needle, swinging on a brass divided circle 12 cm in diameter .... 60.088. -- idem, simpler, on wood, Figure ................... 60,089. Declination Needle, on glass graduated circle, Figure, for objective demonstration with the aid of the horizontal projection apparatus t 1. 0. 0 0.18.0 0. 7. d d. 9. d 60.090. Dipping Needle, simple, for suspending from a thread (M. P. 10lh edn., IV, 1, Fig. 39; 9th edn., Ill, Fig. 34; Gan.-Man., Fig. 604), with well adjusted needle o. 10. 0 60.091. Dipping Needle, simple, on stand, Figure, with well adjusted needle 0.15.0 60.092. Inclination Apparatus with magnetizing spiral, for demonstration purposes, F i g u r e. for remagnetizing the needle 2. S. d 60.093. Inclinator, with electro-magnet, Figure (Fr. phys. Techn. II, 1, Fig. 577). . . 2. o. o 60,09-1. Indicator of Direction of Field, Figure, consisting of a magnetic needle freely movable in space, in solid frame, with extensible haft, in case 0.12.0 lid. d95. Declinator and Inclinator, Figure, can be used at same time as a galvanoseope; pillar turning in tripod, well constructed and carefully balanced needle J. s. it 60.096. Dipping Circle, Figure, for the projection lantern, with glass scale, with t\\<> terminals; can also be used as galvanoseope 1. 1. d 60.097. Dip Circle, Figure, with canying ring, in mahogany carrying case 1. Id. d 5188, L'II:I:I. 5(191.'. *<:;> Xu. >: Declination, Inclination. 791 60 096. 1 : 3. 63097. 1:4. 60 098. 1 : 5. 60100. 1:5. tt 60 101. 1 : 5. 60 102. 1 : 4. 60 103. 2 : 5. 60.098. Dip Circle, can also be used as galvanoscope, Figure, with carefully balanced £ s. d. magnetic needle, column turning in base divided circle, movable on hinge 2.8.0 60.099. Dip Circle, Figure 60,064, p. 787, can also be used for the fundamental magnetic experiments (see under No. 60,064) 5. 10. 0 60.100. Dip Circle, Figure, with horizontal and vertical circle, on tripod with levelling screws, the needle works in agate bearings. The vertical circle is movable, being 110 mm in diameter ' 3. 10. 0 60.101. - - idem, larger, F i g u r e, vertical circle 150 mm, horizontal circle 100 mm diameter, with round spirit level 7. 10. 0 60.102. Dip Circle, large type, Figure (M. P. 9th edn., Ill, Fig. 35; Gan.-Man., Fig. 611; Gan.-Eein. Fig. 703), with detachable needle working in carnelian bearings, vertical circle 190 mm diameter. The instrument gives accurate data [12. 10. 0 60.103. Dip Circle, Figure, with vernier reading for the circle and with micrometer adjust- ment of the vertical circle; diameter of upper circle: 180 mm 11. 0. 0 Cl. .i7:>:!, 2037, 2038, 5750, 2040, 2041, 2042. 792 Magnetism. N,, tin in:, 60 116. 1 : 2. 60 118. 1 : 1 60 120. 1 : 4. 60 121. 60 119. 1 : 4. Compass with nickel case, watch form, stops when cover is closed. £ s. d. List No. 60,105 60,106 60,107 Diameter of cap 35 40 45 £ 0.5.0 0.5.6 0.6.0 60,108 50 mm 0.6.6 Compass, in metal case, with glass cover and arrestment. List No. 60,109 60,110 60,111 60,112 Diameter 30 40 50 60 £ 0.2.9 0.3.0 0.3.6 0.4.3 60,114. Compass in wood case, 8 cm square, stopping when cover is clo 60,115. - - idem, with winding and terminals for use as galvanoscope 60,116. Compass with sun-dial, Figure 60 mm diameter 60,113 70 mm 0.5.0 •led 0. 4.6 0. 5.6 0. 10. 0 0. .11'. (i (iO. 117. Magnetic Needle with comnass card, on stand. Figure . • 60,118. Precision Compass, Figure, for finding the poles in magnetic fields The instrument is watch form anil is closed on both sides by \\at.-h glasses only, thus renderum the magnetic needle visible. The needle itself is very light, well halan-cd and rests in stones. • io.ll't. Ship's Compass, Figure, in Cardan suspension, on stand, card 80 mm diameter 1. 60,120. Ship's Compass (Fluid Compass), Figure, with card floating on alcohol .... 4. This instrument is specially adapted for explaining the fluid compass. Tin- compass curd floats almost aperiodically in the liquid. The apparatus is the standard model of >hip's compass of the Marine and as such, it is, alonj; with its case, let into the ship's lio\. 0. IL'.O K). o .-».() i i Compasses, Magnetometers. 793 60123. 1 : 12. 60125. 1:10. 60126. 1 : 10. 60,121. Apparatus for Proving that the Total Free Magnetism is equal to Zero, Figure £ »• d. (M. P. 10"' edn., IV, 1, Fig. 43) 0.12.0 60,122. Compass (Friedr. C. G. Muller's) (M. T., Fig. 151) 60,123. Compass (W. Weber's), Figure, graduated in 1/i°, on silvered brass ..... A 20 cm diameter compass with a short powerful magnetic needle is fixed on a polished wood rail, 1.5 m long, divided in centimetres. The needle is suspended on a raw silk fibre and carries a long aluminium pointer and a sheet of mica swinging in a box, for damping purposes. The compass can be moved up and down by means of a screw for the purpose of bringing the magnetic needle into the axis of the magnets to be investigated. 60,124. - - idem, graduated in on silver, with magnifying glass for reading 60.125. - - idem, simple (M. P. 10lh edn., IV, 1, Fig. 45; 9th edn., Ill, Fig. 88), Figure 60.126. Magnetometer (Salcher's), Figure (Ztschr. f. d. phys. u. chem. U. 3, p. 195), very finely constructed, with 2 magnet suspensions in case and 6 bars of Swedish Charcoal Iron A graduated rail turns on a vertical pin, to which a cord pulley is firmly fixed. The rotary bearing for the magnet bars to be tested and for the iron rods possesses a cord pulley of the same size as the one just mentioned, being connected to it by a length of cord. On rotating the rail the bar set up maintains its initial position to the magnetic meridian. The compass case and the disc of the bar-bearing are graduated; the compass itself has a graduation in 1/5° on silver, read by a magni- fying glass. The magnetometer is especially adapted for nautical schools. Of the 6 soft iron bars 1 each is 10, 15, 20 mm thick and 30 cm long, 1 each 25 and 30 mm Iliick and 40 cm long, and 1 35 mm thick and 60 cm long. 1.10.0 7. 10. 0 11. 0.0 2. 5.0 32.10.0 Cl. 2047, 204S, 204». 794 Magnetism. 60 127. 1 : 6. 60 129. 1 : 4. 60130. 1:10. 60,127. School Magnetometer, Figure, consisting of a School Galvanometer (see under), a Resistance Bridge (see under), a Slider for taking magnets of any shape, a Stage for the galvanometer and an Aluminium Bush, graduated, for taking annular weights of each 20 g The apparatus are set up in the manner shown in the Figure. £ s. el. 7. lo. o 60,128. Slider, Stage and Aluminium Bush, alone 60,12!). Magnetometer (Weber's), Figure (M. P. 10th edn., IV, 1, Fig. 48; 9th edn., Ill, Fig. 91), for proving the intensity of terrestrial magnetism, with good plane mirror . 1. in. o 3. 15. 0 60,130. Coulomb's Torsion Balance, Figure, for measuring magnetic forces and for experiments on electric attraction and repulsion (Gan.-Eein. Fig. 690). 3.15.0 The following are supplied as accessories to the balance: (1) for experiments on magnetic repnl -ion: 1 magnetic needle uiih Mand. 1 bar magnet for setting in the suspension l>n\\. 1 liar magnet for deflecting the previous magnet, 1 brass bar of the same si/.e as llie first magnet. 2 brass rods with knobs; (2) for the experiments nn electric repulsion: .'i ebonite rods with niekelled balls. - We give complete description and directions for use with the apparatus from which the experiment- can be made with ease and certainty. cl. 9051, So. BO 134. Magnetometers. 795 60132. 1:17. 60131. 1:7. 60 134. 1 : 9. 60 133. 1 : 10. 00,1. '51. Apparatus as suggested by Fischer-Meutzner, Figure, for Coulomb's Law on the Decrease of Magnetic Force with Distance (Ztschr. z. Ford. d. phys. U. 1885, p. 229) An astatic needle is suspended in front of a vertically placed bar magnet. The time of swing is altered by approaching or removing the bar from the needle. OOJ.Hii. Luminous Needle (Friedr. C. G. Miiller's), for magnetometry and galvanometry (Ztschr. f. d. phys. u. chem. U. 22, p. 1), Figure, with following accessories: short magnet bar with lug and cap, 2 long steel wire magnets, 2 m long; 1 coil for Eemancnce experiments with compensating winding and 4 test bars; 1 tangent galvanometer ring 300 mm in diameter; 1 idem 100 mm diameter; 1 multiplier frame; 1 astaticising magnet; 1 wire figure in circular, square and triangular form for shewing a special of the Biot-Savart Law. The luminous needle has an excellent damping system £ s. d. 2. 0.0 10.0 133. Dynmeter (Friedr. C. G. Miiller's), Figure (M. T., Fig. 157), with a small bar magnet for same 100x10x6 mm, with agate cap, on stand . . . 2.10.0 ^0,134. Magnetic Balance (Kleiber's), Figure (Kleiber, Physik f. Gynm., Fig. 293) . . 1. 0. 0 C'l. 5505. .-.Till. 5U5S, 4508. 796 Magnetism. No. (id IX, — 60 139. 1 : 7. 60137. 1:10. 60 140. 1 : 8. 60.135. Pole Balance (Grimsehl's), for determining the pole-density of magnetic needles, Figure (Ztschr. f. d. phys. u. chem. U. 16, p. 334) Three stands carry: 1 knitting needle which takes the form of a balance with rider scale; 1 vertical rule and 1 horizontally arranged magnetic knitting needle which is adjustable vertically. The repulsion of the two similar poles of the knitting needles is taken up by rider weights and so measured. 60.136. - - idem, especially for determining the horizontal intensity of terrestrial magnetism, Figs. 60,135 and 60,136 (Ztschr. f. d. phys. u. chem. U. 16, p. 337) 60.137. Magnetic Pendulum, Figure, as suggested by Bussner (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 96), for subjective and objective observation; independent appa- ratus, on polished stand The apparatus is used for proving Coulomb's Magnetic Law, for proving that the total affect of a short magnetic rod on a single pole equals -' for determining the magnetic moment and the pole-density of a magnetic bar, the field-density of a short and a long coil (Biot-Savart's Law), the magnetic induction and hysteresis of iron. A complete description and instructions sent on application. Given in are: 1 short and 1 long bar magnet; 1 short and 1 long magnet coil, and 1 adjustable projection lens. 60.138. -The same apparatus, for placing on the optical bench of projection apparatus. Price without stand or projection lens <>o, 1 39. Apparatus for determining the horizontal component of terrestrial magnetism, F i g u r e, Kussnci's (Zlschr. f. d. phys. u. chem. V. 20, 1907, p. 172) Complete description on application. ii. I. 60,140. Thermo-magnetic Apparatus, Figure .................... _. 5. 0 A star formed of iron bars is arranged to rotate in front of the poles of a powerful magnet. In the position where ;m iron bar is attracted by the magnet, the latter is heated to a red heat b\ a Bunsen burner which is set up and it thereby loses the magnetism produced in it by distribution. and the next bar is attrarted by the magnet. The star is therefore set into slow rotation. 01. 5580. 5589, .So. 60 156. Static Electricity. 797 60 141. 1 : 5. 60 153. 1 : 6. 60 155. 1 : 5. Static Electricity. 60.141. 1 Flint Glass Rod, 1 Ebonite Rod, 1 Piece Catskin and 1 Piece Amalgamated Felt, Figure 60.142. 4 Rods of Glass, Ebonite, Sealing Wax and Sulphur, 1 Rubber of Amalgamated Felt, 1 Piece Catskin, 1 Brass Rod with glass handle, 1 Piece Steatite with ebonite handle 60.143. Collection of Apparatus for the Fundamental Experiments on Magnetism, Frictional, Contact and Thermo-electricity, in wood box, F i g. 60,065, p. 787 The box contains: 2 bar magnets, 1 double hook for suspending the magnets; 1 magnetic needle; 1 ebonite rod; 1 glass rod; 1 rubber; 1 insulating stand; 1 electric needle; pithballs with stand; 1 glass rod with brass c*.p; 1 ebonite rod with brass cap; 1 Voltaic cell with contact bow, and 1 thermo- electric rectangle. 60.144. Flint Glass Rod, 350 mm long, 15 mm thick, with amalgamated felt rubber, for gene- rating positive electricity 60.145. - - idem, larger, 500 mm long, 20 mm thick, with amalgamated felt rubber . . 60.146. Ebonite Rod, 350 mm long, 15 mm thick, with 1 Piece Catskin as rubber, for gene- rating negative electricity s. d. 5.0 0.0 6.0 60,147. - - i d e m, larger, 500 mm long, 25 mm thick, with catskin rubber j 0 <>(U 48. Flint Glass Tube, with amalgamated felt rubber 60.149. Fox-tail Rubber 60.150. Catskin Rubber JO 60.151. 2 Ebonite Rods, 300 mm long, 12 mm thick, with rubber and with double hooks for suspending on silk threads, for showing the repulsion of the same kinds of electricity 60.152. Brass Rod, with ebonite handle and rubber (Gan.-Eein, Fig. 708) 60.153. Steatite Piece with ebonite handle (Kolbe's), Figure, for electrostatic experiments 0. 2.0 0. 5.0 0. 3.0 0. 5.0 0. 3.0 0. 5.0 0. 1.0 (Kolbe-Skellon, Introduction to Electricity, Part I, pp. 13 and 15) (i(M54. - idem (Weinhold's), with groove (W. D., p. 639) 0. 60,155. 2 Double Hooks, for suspending rods and tubes of wood, glass, ebonite, paper, etc., Figure (W. D., Fig. 422 [398]) 6(i.l 5U. Paper Tube Drying Device (W. D., Fig. 423 [399]) 0 6.0 7.0 5.0 4.0 3.0 2.0 CM. 2056, 3703, 2057. 798 Static Electricity. No. 60 l.-,7 — 60160. 1:6. 60 162. 1 : 6. 60 163 and 60 164. 1 : 6. 60158. 1:12. 60 166. 1 : 4. 60.157. 5 Rods of Wood, Glass, Ebonite, Sealing Wax and Sulphur, for suspending by means £ * 60.158. Electric Horizontal Pendulum, Figure (W. D., Fig. 425 [408]), with hollow alu- minium ball, on glass rod, on stand with levelling screws. Highly sensitive and protected by the use of the aluminium ball instead of the glue ball ............ 1. 4. u 60.159. Simple Electric Pendulum (Gan.-Man., Fig. 615, and Gan.-Eein., Fig. 705) .... 0. •>. o 60.160. Double Electric Pendulum, Figure, on insulated stand (Gan.-Man., Fig. 617, and Gan.-Eein., Fig. 709) ............................. 60.161. Double Electric Pendulum, Kolbe's, Figure, with two rotary arms (Kolbe-Skellon, Introduction to Electricity, Part I, Fig. 2) ................... 60.162. Apparatus for the Fundamental Electrical Experiments, as suggested by Gustav Wiedc- tnann, Figure, comprising a- stand to which is fitted an insulated needle on which a glass rod turns. At the ends of this rod are fitted each 1 ebonite and glass disc. In addition there are: 2 ebonite and glass slabs on insulating handles, 2 rubbers, 1 of amalgamated felt, the other of cat-skin, and 1 rod with amalgamated leather on one end and catskin on the other, in case (Ztschr. f. d. phys. u. cliein. I". 4, p. 196) . . 60.163. Glass Tube, closed at the ends, and with cap fused in, turning on insulating stand. Figure ......................... .......... 60.164. Ebonite Rod, with brass cap, on insulating stand, rotary, Figure ....... 60.165. Insulating Stand of No. 60,163, alone ..................... i;. Horizontal Pendulum with two balls, on stand, Figure ........... •2 quid- thin, light, glass balls, 1 being metallically covered, or carried by a thin balance heam which rests on a, point. <; 60.179. Aluminium Leaf Electroscope, as No. 60,178, with celluloid graduated arc, Figure 0. 1(>. o 60.180. Electroscope for placing on the air pump, Figure 0. is. o The glass bulb can be detached from the base and be placed with its polished edge on the air pump. no. 1*1. Electroscope, Chatlock's, Figure, with first-rate ebonite and air insulation, with aluminium leaf, also suitable for projection 0.18.0 60.isi». Aluminium Leaf Electroscope, with unscrewable point, condenser and mica disc, F i <; s. A and B 1, 6. 0 60,183. Aluminium Leaf Electroscope (Kolbe's), Figure, with degree scale 0. 18. 0 (•0,1X1. Electroscope, Figure, with separate condenser and mica disc, for explaining elect roplmnis (\V. D., Fig. 434 [407]) 1. 6. 0 (10.1X5. Condenser alone, with mica disc 0.15.0 60.1S6. Electroscope (v. Bcet/.'s), Figure, for objective demonstration (\V. D., Fig. 4:51} [405]: M. I'. 10"' edn., IV, 1, Fig. Ill ; !)"' edn., 'ill. Fig. 10!!; Gan.-Man., Fig. 618; (lan.- Eein., Fig. 710) 1. 2. 0 If not otherwise desired we supply the elertrox-ope with aluminium leaves, but also witli paper strips if required. Cl. 20«t>. 20B7. 410.-I. LM7i>. DIM. liiuw. -Jiw/.i. -JHTI N"0. 60195*. Electrometers. 801 60 186. 1 : 6. 60 189. 60195. 3. 60 195 a. 5. 60.187. Paper Tube Electroscope (Weinhold's) (W. D., Fig. 433 [406]) .......... 60.188. 2 Cylindrical Wire Baskets, for screwing on Electroscope No. 60,175 to 60,180 (W. D., p. 668 [609]), and 1 Hollow Sphere on insulating handle 60.189. Fork Electroscope (Fischer's), Figure (Fr. phys. Techn. II, 1, Fig. 14) .... 60.190. Electrometer, Szymansky's, Figure, giving deflections to 180° (Ztschr. f. d. phys. u. chem. U. 4, p. 60), with gilt metal parts 60.191. Portable Electrometer, for measuring atmospheric electricity, as suggested by Exner, Figure (M. P. 9th edn., Ill, Fig. 259), in case ....'. 60,191 a. Flame Collector for above, with supports in walking stick form 60.192. Portable Electrometer (Elster and Geitel's), with mirror for reading without parallax (M. P. 10th edn., IV, 1, Fig. 112) -. 60.193. Tangent Electrometer (Carl's), with condenser (Fr. phys. Techn. II, 1, Figs. 22 and 23) 60.194. 2 Glass Rods with glass balls, for enabling the Griinsehl Pole Balance No. 60,135 to be used also as an absolute electrometer 60.195. Electrometer (Dellmann's) (M. P. 9th edn., Ill, Fig. 177), Figure 60,195 a. Electrometer (Kohlrausch's), F i g u r e (M. P. 9th edn., Ill, Fig. 178), with magni- fying glass reading, platinum or <|ii;ntz suspension £ s. d. 0.12.0 0.12.0 0.16.0 2.10.0 2. 5.0 1.10.0 3. 0. 0 2.10.0 0. 8.0 2.14.0 5. 10. 0 il. :,B1R, 3R9, 5810,5815, 2076, 2080. 51 802 Static Electricity. No. 60 196 — 60 200. 1 : 4. 60 201. 1 : 5. 60200a. 1:3. 60 200 b. 1:3. 60 202. 1 : 6. 60 196. 1 : 4. 60 203. 1 : 6. 60 205. 1 : 6. 60.196. Aluminium Electrometer (Kolbe's), Figure (Kolbe-Skellon, Introduction to Electri- £ s. d. city, Parti, Fig. 15) similar to Gan.-Man., Fig. 659, with projection scale for calibrating and amber tubes in ebonite plug, one ball 10 mm diameter, two condenser plates (lacquered) with one ebonite handle, one extra ebonite plug with amber tubes, con- ductor rod and paper leaves 3. o. 0 The sheet iron house of the instrument is 130 mm high, 140 mm wide, 95 mm deep. 60.197. Projection Grade Scale, for inserting in above, divided on mica 0. <>. o 60.198. 2 Sheet Metal Pieces with C-shaped pieces cut away, for quantitative experiments 0. 4. 0 60.199. Hollow Ball, for screwing on, 50 mm diameter, and 2 insulated test balls for graduating 0. 6. 0 60.200. Testing Electroscope (Kolbe's), Figure (Kolbe-Skellon, Introduction to Electricity, Part II, Fig. 79) [ 0. 6. 0 60,200 a. Auxiliary Electroscope (Kolbe's), Figure (Kolbe-Skellon, Introduction to Electri- city, Part II, Fig. 109) 0. 3. 0 60,200 b. Testing Electroscope with long insulated metal handle, Figure 0. 3. 0 60.201. Insulated Wire Fork, as suggested by Kolbe, Figure (Kolbe-Skellon, Introduction to Electricity, Part II, Fig. 81) 0.18.0 60.202. Aluminium Leaf Electrometer (Grimsehl's) (Ztschr. f. d. phys. u. chem. U. 16, p. 5), suitable for projection, Figure 3.10.0 Tnis electrometer is extremely sensitive. An extra ebonite plug, in two parts, and a clamping screw for inserting are given in with the instrument. Tne instrument is built into a brass case and possesses a graduation, going up to 30°, on a mica disc. Glass windows fitted in front and behind render it possible to employ the instrument in con- junction with the projection apparatus. An adjustable discharging electrode serves both for arresting and for increasing the sensitivity of the instrument. Cl. 3454. 4977, 390. 572li. 5711, 3812, 3813, 3X11. No. 60217. Electrometers. 803 60 206. 1 : 6. 60 211 — 60 215. 1 : 6. 60,203. 2 Brass Condenser Plates with one insulated metal handle, Figure 60,204. 1 Copper Condenser Plate and 1 Zinc Condenser Plate 60.205. Additional Accessories for Grimsehl's Electrometer, Figure A zinc and a brass plate, both on brass rods, for showing the varying potential of these metals plunged in an electrolyte; 2 platinum sheets on brass rods for immersing in the same or in different electrolytes; cylindrical dissipation body for showing the discharge action of air, which is ionised by fog, radio-active substances, Rontgen Rays or by an Auer Incandescent Mantle brought near to it; amalgamed zinc plate with brass pin soldered on for showing the discharge action of magnesium tape burned in the neighbourhood of the apparatus on the aluminium leaf charged with negative electri- city; also connecting tube and clamping pieces. 60.206. Graphite Conductor for demonstrating the potential drop in electric leads, as suggested by Grimsehl, Figure (Ztschr. f. d. phys. u. chem. U. 16, p. 11). Price, exclusive of cover plates and without graduation 60,207. - - idem, with graduation £ s, d. 0. 12. 0 0. 6.0 0.15. 0 1.10.0 1.17.0 i 60,208. Liquid Resistance for the Electrometer Leaf 0. 1. 6 60,209. - - idem, for the Electrometer Case 60,210. Yarn for connecting the apparatus Electrometers for investigating Radio-active Substances: "see section on "Radio-Activity". Absolute Lecture Electrometer, as suggested by Prof. F. Braun (Tubingen), Figure (Wied. Ann. 44, p. 771, 1891; Ztschr. f. d. phys. u. chem. U. 5, p. 61; W. and E., Fig. 252). These electrometers can be used as a substitute for the aluminium leaf electroscopes. When a lamp is placed behind them, the readings are visible at a great distance. The electrometers are supplied with the following ranges, and are carefully calibrated. List No. 60,211 Volts 0—1500 Graduated from 100 to 100 £ 2.12.0 60,212 0—1500 500 to 500 2.1.0 60,213 3500 100 to 100 2. 16. 0 60,214 3500 500 to 500 2.4.0 60,215 10,000 500 to 500 Volts 3.6.0 60.216. Extra Price if constructed with Mica Scale and figured for projection purposes . . 60.217. Metal Beaker, with haft soldered on, for graduating the Braun Electrometer (M. T., p. 234) 0. 2.6 0. 1.0 0. 6.0 0. 3.0 Cl. 3815, 2084. 51* 804 Static Electricity. No 60218 — 60 218. 1 : 8 60219. 1:3. 60221. 1:10. 60222. 1:13. 60223. .1:6. 60.218. Electric Balance (Kleiber's), Figure (Kleiber, Phys. f. Gymn., Fig. 261) . . . 60.219. Sine Electrometer (Schwedoff's), Figure (Ztschr. f. d. phys. 11. chcm. I'. 5. p. 235) The rod with the movable leaf can turn about a horizontal axis. After charging the hitter is rotated until the electric repulsion is compensated by the weight of the leaf itself. The capacity of the instrument thereby always remains the same. (io.220. Absolute Electrometer (Korolkow's) (Ztschr. f. d. phys. u. chcm. ['. 20, p. 287), without the apparatus there illustrated (inductor, Leyden jar, Kolbe electrometer) 60,221. Pendulum Electrometer, Odstrcil's, Figure, simpler pattern, for demonstrating Coulomb's Law (Kolbc-Skellon, Introduction to Electricity, Part I, Fig. 30) .... lilt. 222. Odstrcil's Apparatus, more complete pattern, Figure, for demonstrating Cou- lomb's Law (Xtschr. f. d. phys. n. chem. U. 6, p. 224) 60,223. Pendulum Electrometer for verifying Coulomb's Law on the action of electricity at a distance, as suggested by \\Vinhold. Figure (\V. !>., Fig. 120) Coulomb's Torsion Balance: see No. 60,130, p. 7ot. Pile Electrometers and Quadrant Electrometers: sec under Voltaic Electricity. 1. 0. 0 2. 10. 0 3. 0. It 1. 0. 0 3. 10. 0 i. :.. o i I. .Ml! I. 5(111. 4'.H.\ N... Electrometer, Distributing Apparatus. 805 60224 and 60225. 60 229. 1 : 5. 60 226. 1 : 9. 60 230. 1:5 60231. (iu,224. Conductor Ball, 10 cm diameter, on glass pillar with base, with opening at the upper end (M. P. 10th edn., IV, 1, Fig. 124; 9th edn., Ill, Fig. 124; Gan.-Man. Fig. 625; Gan.-Eein., Fig. 716) (ill. 225. Electric Pendulum on insulated stand, Figure, for verifying Coulomb's Law by the swing of the pendulum at various distances (Fr. phys. Techn. II, 1, Fig. 37; M. P. 10th edn., IV, 1, p. 225) <>(). 226. 2 Conductor Balls, on 50 cm high glass pillars with bases, Figure (W. D., Fig. 427 [403]), with brass rod pointed at one end and provided with a ball at the other (W. D., Fig. 436 [409]), and with a connecting tube 1 m long 60.227. Test Ball on Ebonite Rod (M. P. 9th edn., Ill, Fig. 115) 60,22S. Test Disc on Ebonite Rod (M. P. 10th edn., IV, 1, Fig. 125; 9th edn., Ill, Fig. 116) 60.229. 2 Conductors, one of which can be lengthened or shortened by a sliding bush, on insulating ebonite handle, Figure (M. P. 9th edn., Ill, Fig. 121) 60.230. Distributing Apparatus (Eiess1), Figure (W. D., Fig. 431 [404]; M. P. 9th edn., Ill, Fig. 114) 60.231. Distributing Apparatus (Wesselhoft's), Figure (Fr. phys. Techn. II, 1, Fig. 45) . £ s. d. 0. 13. 0 0. 8. 0 1. 14. 0 0. 1.0 0. 1. 0 0.18.0 1. O.o 0. 15. 0 Cl. 5614, 2087, 9086, 2088, &607. 806 Static Electricity. Xn. Ill i 232 — - B A •* 60 234. 1 : 8. 3S -— " . .-:..-;=^-= 60 235. 1 : 8. o , 60236. 1 : 6. 60 238. 1 : 5. 60.232. Distributing Apparatus, Kreb's, Figure (Ztschr. z. Ford. d. phys. U. 1, p. 56), £ with 2 different distributing cylinders 1. 16. o 60.233. Apparatus for Generating Electricity by Influence, consisting of 2 conductors on 2 electroscopes, Figure (W. and E., Fig. 253) 1. 4. 0 60.234. Hemispherical-Ended Cylinder, on glass pillar with base, F i <; u i e (M. P. 10lh edn., IV, 1, Fig. 130; 9lh edn., Ill, Fig. 131; Gan.-Man., Fig. 628), for showing that the density of electricity at the ends of an elongated conductor is greater than in the centre . . 0. 16. o 60.235. Large Egg-Shaped Conductor, for the same experiment, Figure, nickelled (Gan.- Eein., Fig. 721) I.Jo, 60.236. Weinhold's Apparatus, Figure (W. D. Fig. 439 [412]; M. P., 10th edn., IV, 1, Fig. 131; 9th edn., Ill, Fig. LSI'), for the same experiment 0. 6. <> 60.237. Sheet Iron Hollow Sphere, with copper wire 1.5 m long and 0.4 mm thick, on insu- lating handle (W. 1)., Fig. 442 [415]), for placing on balls No. 60,226 0. 1. <> 60.238. Electric Blind for varying the density of electricity with the si/.e of conductor. Figure (M. P. 10th edn., IV, Fig. 134; 9lh edn., Ill, Fig. 175) o. li'. o I, L>'W, 2095, 20%, L'n'.i?. No. 60245. Conductors. 807 60 240 A. 1:6. 60 242. 1 : 5. 60245. 1:9. 60,239. Conductor with sharp point, on stand (Kleiber, Phys. f. Gymn., Fig. 272; Gan.-Man., . £ ». d. Fig. 626; Gan.-Eein., Fig. 755) 0.15.0 60,240. Apparatus (Mach's), Figs. A and B, for demonstrating the variation of density of electricity with the size of the conductor The apparatus consists of 4 brass caps telescoping one in the other on insulating stand, with paper pendulums and with glass hooks for withdrawing. 60,241. - - idem, double the size of preceding 60.242. Faraday's Beaker, Figure, for showing that the electric charge of a body is pro- portional to the quantity of electricity conducted into it (Fr. phys. Techn. II, 1, Fig. 100) The apparatus consists of a beaker of wire netting on insulating stand. The metal bottom of the beaker possesses a hook for a connection with the electroscope; 6 balls of equal size serve for conducting an increasing load to the beaker. 60.243. Hollow Cylinder of Metal, for showing that free electricity is present on the surface, Figure, on stand The cylinder carries 2 pairs of elder -pithballs; when charged the external balls only diverge. 60.244. Brass Ball on Insulating Stand, with 2 surrounding hemispheres with glass handles, as suggested by Coulomb, Figure (M. P. 9th edn., Ill, Fig. 125; Gan.-Eein., Fig. 717), for demonstrating that electricity resides on the surface 60.245. Pfaundler's Apparatus for the same experiment, Figure (M. P. 10th edn., IV, 1, Fig. 127; 9th edn., Ill, Fig. 127), consisting of a wire cage and insulated metal plate with conducting and insulating lead to the electroscope. Price, without electroscope 0. 18. 0 2. 0.0 0. 15. 0 1. 0.0 0. 18. 0 1. 7.0 CI. 2100, 2091, 2092, 2099. 2101, 2093. 808 Static Electricity. NIL (ill 246 — 60252. 1:7. 60 249. 1 : 7. 60253. 1:10. 60 258. 1 : 6. 60.246. Aluminium Leaf Electroscope with Lead Cap (W. D., Fig. 438 [411]) and glass vessel, £ for the same experiment 0. 10. o 60.247. Lead Cap alone, fitting No. 60,176 0. 3. () 60.248. Faraday's Muslin Net, for the same experiment (M. P. 10lfi edn., IV, 1, Fig. 129; 9"1 edn., Ill, Fig. 130; Gan.-Eein., Fig. 720) 0. 8. 0 60.249. Leyden Jar with large Hollow Ball having a wide opening, and with Test Ball, F i g u r <•, for the same experiment 0. 12. 0 60.250. Apparatus for the same experiment, consisting of a metallic hemisphere on base and a spherical dish for covering the same at some millimetres distance from the top, tin- dish having a metal pin with insulating handle for establishing a metallic connection with the hemisphere (Gan.-Eein., Fig. 718) 1. 0. 0 60.251. Wire Cage in the form of a cheese-plate cover, with a vane inside and outside, tot the same experiment, on insulated stand 0. 15. o 0(1,252. Wire Spiral with ebonite handle and pithballs, as suggested by Kebenstorff, for showing that a free charge is not present in the interior of a hollow body, Figure. without the elect ropliorus illustrated (». 6. 0 The wire spiral is placed upon a charged electrophorus and the balls are placed inside: they remain motionless as no free charge is present here. If. however, the spiral is compressed, the balls fly apart. 0(1,253. Lippmann's Apparatus for Demonstrating the Equality of Induced and Inducing Elec- tricity and the Screen Action, Figure (Fr. phys. Teclwi. II, 1, Fig. 143; Can. -Man.. Fig. 030). Price, without the electroscope illustrated 2. 5. 0 The illustration shows the twn experiments which can lie carried out with the apparatus. The experimental arrangement on the rifjht hand side shows the complete apparatus and also an electro- scope not included in the price. ci. M74, -'<>:u. "266. Noack's Apparatus for the Study of Potential. 809 60261, 60268, 60269, 60271, 60274, 60275. 1 : 10. 60262. 1 : 16. 0 v I 60 263 — 60 265, 60 267. 1:16. 60266,60274. 1:16. Noack's Apparatus for the Study of Potential. (Ztschr. f. d. phys. u. chem. U. 6, 1892/93, p. 221.) (10,196. Aluminium Electrometer (Kolbe's), Fig.' 60,196, p. 802 (Kolbe-Skellon, Introduction to Electricity, Part I, Fig. 15), with calibrated projection scale and amber tube in j ebonite plug, 1 ball 10 mm in diameter, 2 condenser plates (varnished) with ebonite handle, 1 extra ebonite plug with amber tube, conductor rod and paper leaf .... Zamboni Pile (Elster and Geitel's), modified by Noack, of gold and silver paper with inlaid brass discs with projecting tongues, for taking off a divided potential also List No. 60,255 60,256 No. of pairs of plates 1000 2000 Diameter of plates mm 28 28 £ 1. 0. 0 1. 7. 0 £ s. d. 60.257. Electrometer (Bohnenberger's) 60.258. Water Battery, F i g u r e, with 144 copper-zinc cells in ebonite frame 60,222. Odstrcil's Apparatus, F i g. 60,222, p. 804, proving Coulomb's Law . . 60.260. 2 Small Electroscopes 60.261. Sheet Iron Tube, 30 cm length of side, Figure 60.262. 2 Sheet Brass Hollow Cylinders, F i g u r e, 50 cm long, 20 cm diameter, open at both ends, one of which can be closed by a lid, on ebonite pillar with iron base . . 60.263. Sheet Brass Hollow Cylinder, Figure, 20 cm long, 8 cm diameter, with carrier bent at right angles on iron base 60.264. Insulating Table, of ebonite, F i g u r e, 20 cm diameter, with ebonite pillar 50 cm high, on iron base . . . . • 60,265. Paraffin Plate, Figure, 20 cm diameter, 5 cm thick 3. 0. 0 tio.'j(>6. 2 Fixed Sounders, with ebonite pillar and porcelain base, Figure, with solid balls of 2 cm and hollow cylinders of 6 cm . 2. 15. 0 3. 0. 0 3.10. 0 1. 13. 0 0. 5. 0 2. .5. 0 0.12.0 0.12.0 0. 4.6 0. 10. 0 Cl. 2102, 2103, 2104, 2105. 810 Static Electricity. No. 60267 — 60 279. 1 : 15. 60300. 1 : 10. 60.267. Adjustable Sounder with brass ball, rubber hose and gas outlet tip, on ebonite pillar £ » 60.306. Brass Rod with 2 Balls, nickelled (Fig. 26 a) ... 1 0.1.0 For Kolbe Projection Apparatus: see Vol. I of this Price List, p. 167, Nos. 50,855 — 50,866. 60.307. Conical Conductor, Figure (Fig. 14), for proving the different distribution of electricity on the surface of an insulated conductor, nickelled, with 3 test balls of 15, 10 and 5 mm, on ebonite hafts 1. o. »> 60.200. Test Electroscope, F i g. 60,200 on p. 802 (Fig. 17) 0. «>. u 60.309. Wire Net Cylinder with sheet iron bottom, for screwing on the electrometer (Fig. 20) o. 3. o 60.310. Ebonite Rod with amalgamed leather rubber (Fig. 20) 0. 2. 0 60.311. 4 Nickelled Hollow Balls of 20, 10, 10 and 5 cm diameter on insulating stands (Fig. 22), for experiments on electric density with equal charge 2. (i. <> If Ball No. 60,199 is already available, this can be omitted, and the price it then reduced to £ 1. 16. 0. 60,183. Aluminium Electroscope with degree scale, Fig. 60,183 on p. 800 (Fig. 26 B) . . 0. is. o . White Metal Sheet Plate for the same (Fig. 27) 0. l.o 60.316. Wire Net Cylinder and Sheet Iron Plate, Figure (Fig. 28), for showing that elec- tricity resides only on the surface 0.10.0 60.317. Candle Holder with wire net for placing on same (Fig. 29) 0. .">. o 60,221. Pendulum Electrometer (Odstreil's), simple construction (Fig. 30), sec Fig. 60,221 on p. 804 I. 0.0 60,319. 1 Pair Air Condenser Plates (Fig. 34), 15 cm diameter, polished quite plane, nickclled. with ebonite handle, on insulating stand and with 1 mica plate lit cm diameter . . 1. 8. u CI. 2111, 2114, 2116. No. 80 337. Electrostatic Apparatus as suggested by Kolbe. 813 60 325 A. 1:5. 60 325 B. 1:8. 60 337. 1 : 4. 60334. 1:10. Mica Plates for Condensers, singly. List No. 60,320 60,321 60,322 Diameter mm 120 150 190 Each £ 0. 1. 0 0, 2. 6 0. 5. 0 60,200 a. Small Auxiliary Electroscope, on base (Fig. 34), Fig. 60 200 a on p. 802 .... (ill, 324. Standard Condenser (Fig. 37), for screwing on aluminium electroscope No. 60,183, 80 mm diameter, polished quite plane and varnished, in case, for calibrating the electrometer 60.325. Capacity Meter, Figs. A and B (Fig. 42), for Leyden jars, hollow balls, etc., without the Leyden jar and electrometer illustrated in Fig. B For the experiment the extra ebonite plug with the paper leaf must be inserted in the electrometer. 60.326. Air Condenser, on Stand, (Fig. 43) with sliding plates and millimetre graduation . 60.327. Paraffin Plate, 180 mm in diameter, 20 mm thick, with ebonite handle, for the Air Condenser . . 60.328. Ebonite Plate, 180 mm diameter, 10 mm thick 60.329. Mica Disc, 180 mm in diameter, 1 mm thick 60.330. Mica Disc, thin, lacquered on both sides 60,540. Apparatus for Igniting Ether or the like (Fig. 47), F i g. 60,540 on p. 826 . . . 60,388. Model of a Dubrowsky Influence Machine, Figs. 60,388 A and B on p. 817, with fixing clamp (Fig. 48, see also Ztschr. i. d. phys. u. chem. U. 9, p. 223), with an exciter plate, a Leyden jar and connecting leads, without Geissler tube 60,333. Small Amalgamated Zinc Plate with hook (Fig. 53) iio..'13-l. 2 Induction Spirals, Figure (Fig. 57), on ebonite plates with handles, for demon- strating electric induction (Gan.-Kein., Fig. 969) 60,335. Candle Holder with ebonite handle and platinum wire (Fig. 60) 3<». Paraffin Block for insulating the electrometer (Fig. 60) <;<».. ">37. Apparatus for Electric Lines of Force, Figure (Fig. 62), with brass ring fur screen effect . £ s. d. 0. 3.0 0. 18. 0 1. 8. 0 2. 5.0 0. 3.0 0. 6.0 0. 6. 0 0. 4.0 0.10. 0 •2. 8.0 0. 0.6 1. 4. 0 0. 4.0 0. 6. 0 0. (i. 0 Cl. 5585, 2118 5417, 2119. 814 Electrostatic Apparatus. Electrophorus. No. 60338 — 60340. 1:14. 60 358. 1 : 6. 60338 and 60339. 1 : 10. 60 362. 1 : 5. 60.338. Electrometer for Atmospheric Electricity, Figure (Fig. 63), with volt scale on plate £ » . o 60.347. Ebonite Rod (Fig. 1), 40 cm long, 20—25 mm thick 0. 5. () 60.348. Piece of Steatite, with ebonite handle (for experiments on pp. 13 and 15), with borinu fitting for the stand of the conical conductor (Fig. 18) j 0. 5. o 60,360. Ebonite Electrophorus, 32 cm diameter 0. 18. 0 60,583. Leyden Jar, collapsible, 26 cm high (Figs. 39 and 42) 0.14.0 60,580 Leyden Jar with fixed foiling, 26 cm high (Fig. 56) 0. 8. 0 60,365. Winter's Frictional Electricity Machine (Fig. 44), 36 cm diameter, with iron base and ebonite axis 4. 0. 0 60,370. - - idem, with wood base and glass axis 3. 10. 0 60,301. Topler's Self-Exciting Influence Machine, 36 cm diameter 3. H>. ») 60,435. Wimshurst's Machine (.self-exciting), with ebonite plates 35 cm diameter 3.10.0 Electrophorus. Electrophorus, of ebonite, F i g u r e, with metal base, double walled metal cover on ebonite handle and with burled silk rubber ((Ian. -Rein., Fig. 738). List No. 60,357 60,358 60,359 60,360 Diameter cm 17 '2\ L'<> 32 £ 0. 10. 0 0. 12. 0 0. 15. 0 0. 18. 0 Cl. 2121. 2IL"_'. 2tL'ti, 2123. No. 60369. Electrophorus. Electrical Machines. 815 60 363. 1 : 9. 1 60 364. 60365 — 60369. 1:8 — 1:16. 60.361. Electrophorus of Palmier! insulating material (W. D., p. 659 [600]), 26 cm, with metal £ s. d base, double walled metal cover with ebonite handle and burled silk rubber .... 0. 12. 0 60.362. Electrophorus of ebonite, Figure, 21 cm diameter, with metal cover and auxiliary apparatus, both in box 0. 18. 0 Auxiliary apparatus: 1 small Leyden jar, 1 chime of bells, 1 electric wheel, 1 set dancing balls, 3 elder pith figures, 1 discharger, 2 electric pendulums, 1 ebonite plate for Lichtenberg's dust figures, 1 set instructions. 60.363. Tyndall's Electrophorus, Figure (Tyndall, Heat, Fig. 23) 4. 0. 0 The cover of the electrophorus is suspended from a balance. When the Electrophorus is excited and the cover placed on, a considerable weight is necessary to lift it off. The beam can be used both as an ordinary balance and a hydrostatic balance when the electrophorus is detached. Frictional Electric Machines, Influence Machines and Auxiliary Apparatus. 60.364. Bar Machine (Grimsehl's), Figure (Ztschr. f. d. phys. u. chem. U. 15, p. 284), for demonstrating the mode of action of the frictional electricity machine, especially the electricity of the rubber - | 1. 8. 0 Disc Machine, Figure (W. D., Fig. 446 [419]), with iron base and ebonite axis, solidly constructed. List No. 60,365 60,366 60,367 60,368 60,369 Diameter of Discs cm 36 42 50 60 70 - £ 4. 0. 0 5. 0. 0 6. 10. 0 8. 0. 0. 10. 0. 0 Cl. 2124, 5615, 2125. 816 Frictional Electric Machines, Influence Machines and Auxiliary Apparatus. No. 60 370 — 60 380. 1 : 8. 60370 — 60374. 1:6—1:12. 60 381. 1 : 6. 60 384. 1 : 8. Disc Electric Machine, Figure, with wood base and glass axis, disc mounted in wood: List No. 60,370 60,371 60,372 60,373 60,374 Diameter of Discs em 36 42 50 HO 70 £ 3. 10. 0 4. 0. 0 5. 0. 0 6. 10. 0 8. 0. 0 Winter's Ring for the preceding machines, for considerably increasing the percussive distance. List No. 60,375 60,376 60,377 60,378 60,379 £ s. il. Diameter cm 36 £ 0.15.0 42 0. 18. 0 1.4.0 (id 1. 10. 0 70 1. 16. 0 60,380. Electric Machine, Figure, simple construction, with 26 em diameter disc, without ring 60,381. Small Electrical Machine, Figure, for exciting influence machines 00,: W2. Electrical Machine (Ramsden's), Figure, with 2 rubbers and 2 conductors, on polished wood table, elegantly const meted, disc 05 cm diameter ((Ian. -Man., Fig. 661; (lan.-Kein.. Hg. 736) 60,383. Kienmayer's Amalgam per 75 g 00,384. Water Influence Machine, Figure (VV. I)., Fig. 444 [417]) <;o.:;.s5. Sand Influence Machine 60,386. Armstrong's Steam Electrical Machine, simplified model, without steam boiler . . 00,387. Steam Generator for above, gas heated 1. Ki.o l.io. o 16. (i.o o. l.o 2. lo. o 3. o. o 6. o. o S. 0. 0 Cl. 5715, 5803, ;V«>I, 21:111. No. 6039«. Influence Machines. 817 60382. 1 : 10. 60 388 B. 1:10. 60 388 A. 1 : 10. 60389 — 60396. 1:5—1:13. t'.o.MXS. Model of a Dubrowski Influence Machine, F i g s. A and B, with fixing clamp (Ztschr. £ s (1 f. d. phys. u. chem. r. 9, p. 223), with an exciter plate, a Leyden jar and connecting leads, without Geissler tube 2. 8. 0 Self-Exciting Influence Machine, as suggested by Topler, with 1 fixed and 1 rotating plate, can be recommended as most practical in all respects; without ebonite pillars, combs resting on the fixed axis, stand of polished alder wood. List No. 60,389 60,390 60,391 60,392 60,393 60,394 60,395 60,396 Diameter of rotating 1 no 01 of> 41 47 KO 57 62 cm plates J £ 1. 15. 0 2. 10. 0 3. 10. 0 4. 5. 0 6. 0. 0 7. 0. 0 11. 10. 0 16. 0. 0 Cl. 2129. 4109, 4108, 2131. 52 818 Static Electricity. NIL tin :;:i7 60397—60406. 1:6 — 1:24. 60417—60424. 1:11 — 1:27 60426 — 60430. 2:7—1:7. 60407 — 60416. 1:8—1:27. Self-Exciting Influence Machine, as suggested by Topler, with 1 fixed and 1 rotating plate, £ *• Figure, with massive ebonite pillars on which the discharging combs are placed, in order to be able to remove the plates forth; with stand of polished mahogany. List No. 60397 60,398 60,399 60,400 60,401 60,402 60,403 60,404 60,405 60,406 26 31 36 41 47 52 57 62 75 !>() cm £ 3. 10. 0 4. 10. 0 6. 0. 0 7. 5. 0 9. 5. 0 10. 10. 0 15. 15. 0 20. 0. 0 27. 0. 0 30. 0. 0 Self-Exciting Influence Machine, as suggested by Topler, Figure, with 2 fixed and 2 ro- tating plates, base and pillars of mahogany, discharging cumtis fixed on ebonite pillars, very neatly constructed and producing twice the <|iiantity of electricity as those with only two plates. List Xo. 60,407 60,408 60,409 60,410 60,411 60,412 60,413 60,414 60,415 60,416 26 31 36 41 47 52 57 62 75 90 cm £ 6.15.0 8.10.0 11.0.0 13.10.0 17.5.0 19.0.0 25.0.0 29.5.0 32.10.0 41.5.0 Cl. 5707, .V.1I9. 2134, 5709. No. 60441. Influence Machines. 819 60431 and 60432. 1 : 10 and 1 : 12. 60433 — 60438. 1:5 — 1:10. Self-Exciting Influence Machine, as suggested by Topler, Figure, with 4 rotating and £ s. d. 4 fixed plates, wood parts of walnut, very elegantly constructed: List No. 60,417 60,418 60,419 60,420 60,421 60,422 60,423 60,424 )iamet^a°tfegrotatinS } 36 41 47 52 57 62 75 90cm £ 15. 0. 0 18. 0. 0 21. 0. 0 24. 0. 0 29. 5. 0 37. 10. 0 45. 0. 0 56. 5. 0 Self-Exciting Influence Machine, as suggested by Topler,"*1 Figure, with 2 rotating and 1 fixed plate, without ebonite pillars, producing half as much electricity again as the machines with only 2 plates. List No. 60,425 60,426 60,427 60,428 60,429 60,430 •Diameter of rotating plates 26 31 36 41 47 52 cm £ 2. 0. 0 2. 15. 0 4. 0. 0 4. 15. 0 6. 15. 0 8. 5. 0 Self-Exciting Influence Machine (Wimshurst's), Figure, with double rotation, with 2 glass plates, polished base. These machines work without alternation and are independent of atmospheric humidity (Gan.-Man. Fig. 667; Gan.-Kein. Fig. 747). List No. 60,431 60,432 Diameter of plates 26 31 cm £ 1.10.0 2.0.0 Self-Exciting Influence Machine (Wimshurst's), Figure, with double rotation, with two ebonite plates and wood stand. List No. 60,433 60,434 60,435 60,436 60,437 60,438 Diameter of plates 25 30 35 40 '45 50 cm £ 1. 10. 0 2. 10. 0 3. 10. 0 4. 10. 0 6. 0. 0 7. 0. 0 Self-Exciting Influence Machine (Wimshurst's), Figure on p. 820, with double rotation and 2 glass plates, base-board of mahogany, insulating pillars of ebonite, with iron supports and drive. List No. 60,439 60,440 Diameter of plates 41 52 £ 4.15.0 6.15.0 60,441 62 cm 8.5.0 Cl. 5710, 29 F. 52* 820 Static Electricity. 60439 — 60441. 1:8 — 1:12. 60442 — 60463/69. 1:16 60448 and 60449. 1:10-1:17 60450 — 60453. 1:10—1:18. Cl. 570H, 21 in. 2137, i?:i3. Xn. IW461. Influence Machines. 821 60458 — 60461. 1:10—1:18. 60 470. 1:7 — 1:14. Self-Exciting Influence Machine (Wimshurst's), double rotation, with 2 glass plates, specially suitable for Franklinization, Fig. 60,442, without table and other accessories illustrated. Diameter of plates List No. With Glass Cupboard £ List No. Without Glass Cupboard £ 52 60,442 16. 0. 0 60,444 11. 0. 0 62 cm 60,443 18. 0. 0 60,445 13. 0. 0 £ s. d. Self-Exciting Influence Machine (Wimshurst's), with double rotation, with 4 glass plates. Diameter of plates 52 62 cm List No. 60,446 60,447 With Glass Cupboard, F i g. GO 442 £ 18. 0. 0 20. 0. 0 List No. 60,448 60,449 Without Glass Cupboard, F i g u r e £ 13. 0. 0 15. 0. 0 Self-Exciting Influence Machine (Wimshurst's), with double rotation, with 8 glass plates, Figure, with four times the effect of the 2-plate machines. List No. 60,450 60,451 60,452 60,453 Diameter of plates 52 62 75 90 cm £ 18. 10. 0 22. 10. 0 32. 10. 0 40. 0. 0 - idem, with 12 glass plates, with six times the effect of the 2-plate machines. List No. 60,454 60,455 60,456 60,457 Diameter of plates 52 62 75 90 cm £ 27. 10. 0 32. 10. 0 37. 10. 0 55. 0. 0 - i d e m, with 16 glass plates, Figure, with eight times the effect of the 2-plate machines. List No. 60,458 60,459 60,460 60,461 Diameter of plates 52 62 75 90 cm £ 35. 0. 0 40. 0. 0 60. 0. 0 80. 0. 0 Cl. 5734, 2142. 822 Static Electricity. \.l 60471. 1:8. Accessories for Franklinization. £ s. -d. 60.463. Rubber Slab, 70x100 cm, 3 mm thick, Figure (p. 820) 1. 4. 0 This slab, of soft rubber, is used in connection with the metal coating listed under No. 60.464 instead of the insulating stool. 60.464. Metal Coating, 50x80 cm, for preceding rubber slab, Figure (p. 820) .... 0. :.. n This metal covering consists of a 0.5 mm thick nickelled zinc sheet with a plug-box. 60.465. 2 Connecting Leads, thickly insulated with rubber, with spring-hook, Figure (p. 820) 0. 12. 0 60.466. Globe on Insulated Stand, Figure (p. 820) 1.10.0 The device can be raised and lowered as well as rotated laterally. 60.467. Franklin Electrode Holder, 50 cm long, with terminal, Figure (p. 820) .... 0. 6. 0 60.468. Brass Sphere, for screwing on the electrode holder, Figure (p. 820) 0. 1. 6 . 60.469. Franklin's Rose, for screwing on the electrode holder, Figure (p. 820) .... 0. lo. d The rose is 13 cm in diameter, being provided with a number of metal points covered \vitli ebonite sleeves. 60,470. Influence Machine, as suggested by Weinhold, Figure on p. 821, plate diameter 45 cm (W. D. Fig. 453 [430]), without alternation, not self excited, with iron frame 5.10.0 1 New High-Capacity Influence Machines. 60,471. Self-Exciting Influence Machine, as suggested by Wommelsdorf, Figure, with sectors embedded on all sides (Ann. d. Phys., 4th Series, Vol. 23, 1907, p. 609), for hand and motor drive, with plates 35 cm in diameter; spark length: 130 — 175 mm, current to 90 micro-amperes 13. lo. o The machines are of very high efficiency and work exceedingly w(.n. They are only constructed with simple rotation and the sectors are completely embedded in ebonite discs. Cl. 4948. No. fill Ml. Influence Machines, Influence Machine Plates. 823 60473 — 60476. 1:6—1:7. High-Capacity Influence Machines, Figure, suitable for teaching purposes as well as for working Rontgen Ray Tubes and for electrotherapeutics, with embedded corrugated sectors. List No. Diameter of Rotating Disc Spark-length mm Tension, volts Current Power requi- micro-amps red H P Price £ s. d. Construction with 1 fixed and 1 rotating plate. 60,473 60,474 45 cm 55 cm Abt, 180- Abt, 240- -225 -275 Abt. 115,000 Abt. 135,000 Abt, 250-^300 Abt. 300— 350 Abt. «/io Abt. 1/10 25. 0. 0 30. 15. 0 Construction with 1 fixed and 2 rotating plates. 60.475 45 cm 60.476 55 cm Abt. 200 — 225 Abt. 115,000 jj Abt. 500 — 600 i Abt. '/s J32. 10. 0 Abt. 240 — 275 Abt. 135,000 jj Abt, 500 — 600 || Abt.1/* J40. 0.0 By entirely embedding the sectors the influence machines are almost completely independent of atmospheric humidity. The plates can be utilised better, as all superfluous radiation is avoided. The machines are self -exciting. If an alternation is desired, e. g. for working Rontgen Ray Tubes or the like, this can be effected by a simple handle. The simple machine with plates 55 cm in diameter has the same output as an 8-plate Wimshurst machine of the same size; the double machine has a higher capacity than a 16-plate Wimshurst machine of the same size. The construction is extra- ordinarily simple and the safety in working therefore large; the space required is exceedingly small. The oblique conductor is arranged to rotate, it can be adjusted over a scale and can also be lirought near the disc or removed from it. The non-rotating plate has lateral adjustment; in the double machine the action of the second plate can be switched out. Machines Nos. 60,473 and 60,474 are arranged for hand and motor drive, Nos. 60,475 and 60,476 for motor drive only. If it is desired to have the latter arranged for hand drive as in Fig. 60,471, they are increased in cost by £ 2. 10. 0. Spare Parts and Auxiliary Apparatus for Influence Machines. Glass Plates for Topler Influence Machines. List No. 60,487 60,488 60,489 60,490 For machines with rotating plate of 26 31 36 41 Rotating plate £ 0. 4. 0 0. 5. 0 0. 6. 0 0. 7. 6 Fixed plate £ 0. 4. 6 0. 6. 0 0. 10. 0 0. 12. 0 60,491 47 cm diam. 0.8.6 0. 15. 0 824 Static Electricity. 0 1112 — 60512. 1:8. 60 526. 1 : 5. 60525. 1 = 3. 60 527. 1 : 8. Glass Plates for Topler Influence Machines. List No. 60,492 60,493 60,494 60,495 60,496 £ s. d. For machines with rotating plate of 52 !><> cm (liain. Rotating plate £ 0. 9. 6 0. 12. 0 0. 15. 0 1. 5. 0 1. 15. 0 Fixed plate £ 0. 17. 0 1. 1.0 1. 5. 0 1. 15. 0 2. 5. 0 Glass Plates for Wimshurst Machines, with double rotation, Nos. 60,431 and 60,431*. and Nos. 60,439 to 60,461. List No. 60,497 60,498 60,499 60,500 60,501 60,502 63,503 60,504 Diameter of plates 26 31 36 41 52 62 75 (»() cm Price each £ 0. 4. 6 0. 5. 6 0. 7. 0 0. 9. 0 0. 12. 0 0. 15. 0 1. 5. 0 1. 15. 0 Ebonite Plates for Wimshurst Double Rotation Machines Nos. 60,433 to 60,438. List No. 60,505 60,506 60,507 60,508 60,509 60,510 Diameter of plates 25 30 35 40 45 50 cm Price each £ 0. 7. 0 0. 9. 0 0. 12. 0 1. 0. 0 1. 5. 0 2. 5. 0 Motor Driving Stand for Influence Machines, comprising direct current motor for connecting ii]) to 65, 110 — 125 or 220 — 240 volts, with speed regulator and gearing: 60,512. For machines with 2 plates to 41 cm diameter, Figure 5. 10. 0 60,513. For machines with 2 plates to 62 cm diameter or with 4 plates to II cm diameter For other Voltages, Larger Machines and for Alternating and Three-phase Current applications should be made to us. Dust-proof Lock-up Cupboards for Influence Machine, simple construction. List No. 60,514 60 515 60,516 60,517 60,518 60,519 60,520 Suitable for Machines 1 26 ;]1 36 41 47 -o ;,7 cm diam. with a plate of J £ 0. 15. 0 0. 18. 0 1. 2. 0 1. 6. 0 1. 12 0 2. 0. 0 2. 8. 0 60,521. Connecting Chain, with hooks at the ends 1 metre 6. 10. o o. 1.0 i i. :,:.;:(. 21 IK. 19811. Jl IT. Auxiliary Apparatus for Influence Machines. 825 a 60 529. 1 : 5. 60530. 1:3. 60 528. 1 : 3. \ \ 60 531. 1 : 3. 60 532. 1 : 7. uO 534. 1 : 4. 60 535. 1 : 7. 60,522. Elastics, lined with Copper Wire and hooks at the ends (W. D., p. 676 [618]) . . (io.523. Argand Burner, with short base, for placing in the influence machine (W. D., Fig. 456 [428]) 51,176. Double Regulating Cock for above, for quickly turning down the jet without extin- guishing it, see No. 51,176 on p. 207 (W. D., Fig. 457 [429]) 60,525. Hygrometer, Figure, for placing in the neighbourhood of influence machine for determining the humidity 60,526. Insulating Stool, wood, with unscrewable porcelain legs, Figure (M. P. 9th edn., Ill, Fig. 164) 60.527. Collection of Auxiliary Apparatus for the Influence Machine, Figure The collection is well got up and comprises: 1 general stand, 1 apparatus for condensing smoke, 1 paper tassel, chimes, 1 electric whirl, 1 fulminating pane and 2 brass chains. A complete description is appended to each collection. 60.528. Chime, Figure (W. D., Fig. 448 [421]), on iron stand 60.529. Chime with Leyden Jar, Figure, can be used at the same time as a Capacity Meter (Gan.-Eein., Fig. 767) 60.530. Apparatus for Igniting Gases, Figure 60.531. Electric Pistol, Figure (W. D. Fig. 449 [422]; M. P. 10th edn., IV, 1, Fig. 153; 9th edn., Ill, Fig. 165) 60.532. Electric Whirl, on stand, Figure (M. P. 10lh edn., IV, 1, Fig. 155; 9th edn., Ill, Fig. 169; Gan.-Man., Fig. 627; Gan.-Eein., Fig. 755) 60.533. - - idem, larger 60.534. Double Electric Whirl, Figure on.535. Paper Tassel, on stand, Figure (M. P. 10th edn., IV, 1, Fig. 152; 9th edn., Fig. 163) £ • 0. s. d. 1.0 0. 5.0 0. 0. 0. 9.0 8.0 7.0 15.0 0. 9. 0 16.0 4.0 0. 5. 0 4.0 6.0 10.0 4.0 Cl. 214H, 2149, 2150, 2151. 5738, 2152, 5 5737. 826 Static Electricity. No. 6o:.:w © 60 538. 1 : 2. 60539. 1:3. 60 540. 1 : G. 60536. 1:4. 60 541. 1 : 30. 60542. 1:15. 60 543. 1 : 5. 60.536. Electric Dancing Balls, Figure, with metal mounts, on stand (M. P. 10th edn., IV, 1, Fig. 150; 9th edn., Ill, Fig. 162; Gan.-Eein., Fig. 754) 60.537. Electric Mortar (W. D., Fig. 477 [452]) 60.538. Apparatus for Igniting Ether, F i.g u r e (W. D., Fig. 450 [423]) U0.539. -- idem, different pattern, Figure (M. P. 9th edn., Ill, Fig. 166) 60,540. --idem, Figure (Kolbe-Skellon, Introduction to Electricity, Part I, Fig. 47) <>o,54l. Apparatus for explaining Potential Difference and Potential Drop, Figure (Hb'fler, Physik, 1904, p. 438), comprising 1 small table with ebonite top, 2 insulating stands, 2 wood rods 3 m long (folding), and 6 electroscopes, without influence machine . . . 60.542. - - idem, vertical pattern, Figure 60.543. Press with Portrait Pattern, Figure, for producing a portrait of Benjamin Frank- lin by an electric discharge A piece of silk is placed on the baseboard of the press and on top of this silk ;i pattern portrait of cardboard; the pattern is coated externally on one side with tinfoil, this side must face upwards. The pattern is then covered with a piere of gold leaf in such manner that it also touches the (wo tinfoil sheets; a second piece of board is placed on top and the press screwed down so as to expose the gold leaf to the discharge. 60.544. Electrostatic Motor, on stand, Figure (Fr. phys. Techn. II, 1, Fig. 88). . . . £ s. d. O.JO. 0 0. L'. 0 0. 1.6 0. 1'. 0 0.10. 0 1.10. (I 0. 15. I) 0.13. o (1. si:.:.. :.Ti7. :,; ran 5739, ::<*(•.. 0. «. 0 is. :.u.->. Auxiliary Apparatus for Influence Machines. 827 60 544. 60545. 1:4. 60 545 a. 1:5. 60 546. 1 : 6. 60547. 1:8. 60 549. 1 : 4. 60 550. 1 : 5. 60.545. Electrostatic Rotary Field Motor, as suggested by Arno, Figure (Ztschr. f.'d. phys. u. chem. U. 7, p. 2) ~. . .' . 1. 5. 0 (50,545 a. - - i d e m, Figure, for building up with Holtz clamps. Price, without latter (cf. No. 60,172) (Ztschr. f. d. phys. u. chem. U. 7, p. 4) 0.10.0 60.546. - - idem, with electric needle, Figure (Ztschr. f. d. phys. u. chem. U. 7, p. 3), without the Holtz clamps illustrated (cf. No. 60,172) 0. 8. 0 60.547. Electrostatic Double Roller, Figure (Ztschr. f. d. phys. u. chem. U. 7, p. 2) . 2. 10. 0 60.548. Electric Thunder Cloud (Kohler's) (Ztschr. f. d. phys. u. chem. U. 21, p. 113) . . 0. 10. 0 60.549. Apparatus for Demonstrating the Electric Action of Points, Figure (M. P. 10th edn., IV, 1, Fig. 154; 9th edn., Ill, Fig. 167) 0.12.0 60.550. Smoke Condenser, Figure, for demonstrating the disappearance of smoke by radiant electricity; height of glass: 31 cm (Gan.-Eein. Fig. 758) 1. 0. 0 Cl. 5016, 5701, 5700, 5702, 5704, 2153, 2151. 828 Static Electricity. No. fiu 60 555. 1 : (i. 60 554. 1 : 4. 60552. 1:4. 60 557. 1 : 5. 60 558. 1 : 4. 60 559. 1 : 5. 60556. 1 : 10. 60 560. 1 : 3. 60.552. Fulminating Tube, F i g u r c, 40 cm long 60.553. --idem, 75 cm long 60.554. Fulminating Flask, Leyden jar 160 mm high and 80 mm wide, coated externally with square shaped pieces 60.555. Fulminating Slab, of glass, Figure, with tinfoil figure pasted on, 22x28 cm, on stand 60.556. Fulminating Slab (Pfaundler's), Figure, with circular shape magnesium powder coating This fulminating slab is worked by a continuous spark-current of an induction coil or an in- fluence machine. The sparks jump from the pointed electrode on to the plate, glide over the magm-sinm coating with an accompaniment of striking luminous phenomena, being finally carried off on the external annular coating of tinfoil. 60.557. Electric Tourbillion, as suggested by Griiel, Figure, for showing the electric effect of points (Kleiber, Pliys. f. Gymn. Fig. 287) 60.558. Cup and Ball, Figure, on stand 60.559. Henley's Quadrant Electrometer (M. P. lolh edn., IV, 1, Fig. 138; 9th edn., Ill, Fig. 144; Gan.-.Man. Fig. till); (lan.-Kcin. Fig. 711), with base, Figure 60.560. Apparatus for Proving that the same Kinds of Electricity repel each other, F i g u r e, consisting of three metal rings which assume right angles relative to each other when charged with electricity »io,56l. Apparatus for piercing Thin Glass, Figure (W. D. Fig. 473 [448]) £ s. (1. 0. 4. 0 0. 6.0 0. 6.0 0. 18. 0 1. 0.0 o. 18.0 0.12.0 0. 12.0 0. ll'. 0 0. 5. (I (1. 2155,21:16. 1711. 171)6, 57&I, 21B1.21f,L', I'liiH. NO. IKK.Tn. Auxiliary Apparatus for Influence Machines. 829 60 567. 1 : 3. 60 568. 1 : 3. £ s. d. 1. 4. 0 1. 4.0 0. 2.0 60.562. Apparatus for Piercing Glass up to 2 mm thick, Figure (M. P. 9th edn., Ill, Fig. 218; Gan.-Man. Fig. 670; Gan.-Eein. Fig. 793) . . . 60.563. - - i d e m, horizontal pattern, for piercing Glass Plates up to 15 mm thickness, Fig u r e (M. P. 9th edn., Ill, Fig. 219), by means of the sparks from an influence machine or an induction coil 60.564. Apparatus for splintering Glass Vessels (W. D. Fig. 474 [449]) 60.565. - - idem (M. P. 10th edn., IV, 1, Fig. 202; 9th edn., Ill, Fig. 220; M. T., Fig. 168), with shielding tube and 6 spare tubes 0. 6. 0 60.566. Insulating Stand with wood base, ebonite pillar and hollow metallic table, Figure 1. 4. 0 60.567. Apparatus for showing the difference between the two kinds of electricity, Figure (W. D., Fig. 451 [424]) 1. 0. 0 60.568. Electric Thermometer (Kinnerslcy's), Figure (W. D., Fig. 476 [451]) 0. 6. 0 60.569. Electric Air Thermometer (Riess'), Figure (W. D., Fig. 478 [453]; Gan.-Eein.. Fig. 790; Gan.-Man. Fig. 669) 2. 0. 0 60.570. Electric Air Thermometer (Grimsehl's) (Grimsehl, Fig. 753) 0. 12. 0 Cl. 1717, 2166. 2168, 171*. 2171. 2169, 217U. 830 Static Electricity. No. 60571 — 60571. 1:3. 60 573. 1 : 8. 60 576 A. 60 576 B. (1. 3. 1. 0. (i. I) I. u 6. (> 60.571. Apparatus for showing the magnetic effect of the Discharge Shock, Figure (M. P. 9lh edn., Ill, Fig. 251; Gan.-Rein., Fig. 792). Price without the Leyden jar shown in the illustration 0. 7. (I 60.572. Apparatus for showing the inductive effect of a Discharge Shock, as suggested by Friedr. C. G. Miiller (M. T. Fig. 169) , 1.10.0 60.573. --idem, as suggested by Eiess, Figure (M. P. 9th edn., Ill, Fig. 738) . . . — idem, as suggested by Kolbe, see No. 60,334 Apparatus for demonstrating Lines of Force, as suggested by Kolbe, see No. 60,337 . 60.576. Apparatus for demonstrating Lines of Force, as suggested by Seddig (Phys. Ztschr. 5, 1904, p. 403; M. P. 10th edn., IV, 1, p. 231), for the line of force images illustrated in Figs. 60,576 A— D (cf. also Gan.-Rein., Fig. 727) 60.577. Electric Egg, Figure, for demonstrating the Electric Phenomena in Vacuo (Gan.- Man., Fig. 677; Gan.-Rein., Fig. 788) 60,577 a. -- idem, Figure, with holders for inserting carbons for producing an arc . 60,577 b. - - idem, entirely of glass 00,578. Geissler Tube, Figure, with glass stopcock and base, for placing on the air pump, for the same purpose Shaking and Rubbing Tubes, as suggested by Geissler. for phenomena in vacuo or in spaces filled with gases, also for flmiresccncc phenomena: see under Geissler Tubes in section Galvanism. Leyden Jars, F i g u re, with excellent insulating properties of flint glass (Gan.-Man., Fig. 653; (Ian. -Rein.. Fig. 765). List No. 60,579 60,580 60,581 16 26 -10 cm high £ 0. 4. 0 0. 8. 0 0. 12. 0 1. 4.0 1. 7. 0 1.10.0 0. 18.0 0. 16.0 Cl. L'172, 1'MVl. .M;J:I. 5626. No fifljsl. Demonstration of Lines of Force. Leyden Jars. 831 60 576 C. 60 576 D. 60 577 a. 1:8. 60 580. 1 : 6. 60 582. 1 : 8. 60 583. 1 : 4. 60577. 1:7. 60 584. 1 : 8. £ s. d. 60.582. Leyden Jar, 26 cm high, Figure, with terminals for both coatings, on wood board 1. 0. 0 60.583. Leyden Jar, Figure, with removable coating, conical Form, with ebonite handle (Gan.-Man. Fig. 657; Gan.-Eein. Fig. 768) 0. 8. 0 60.584. -- idem, cylindrical form, 26 cm high, Figure j 0. 14. 0 I 1. 5627, 562S. 5348. 2174.217.'i.4511, 2176, JII7K. 2177. 832 Static Electricity. No. 60 ;><:. — 60 585 — 60 587. 1:5 — 1:12. 60 596 — 60 598. 1 : 8 — 1 : 20. 60 606. 1 : 5. 60 607. 1 : 6. Leyden Jar Battery, Figure, consisting of 4 jars (Gan.-Man., Fig. 654; Gan.-Bein., Fig. 771, without the electrometer illustrated in the book). £ s. d. List No. 60,585 60,586 16 26 £ 1.12.0 2.8.0 Leyden Jar Battery of 6 jars. List No. 60,588 60,589 16 26 £ 2. 8. 0 3. 12. 0 Leyden Jar Battery of 9 jars. List No. 60,591 60,592 16 26 £ 3. 4. 0 4. 16. 0 60,587 40 cm high 3. 10. 0 60,590 40 cm high 4. 10. 0 60,593 40 cm hiirh 6.0.0 60,594. Cascade Battery with 4 Leyden jars in series, 16 cm high (M. P. 10th edn., I\. 1. Fig. 205; 9"> edn., Ill, Fig. 214; Gan.-Rein., Fig. 77M) t;ii..v.t5. — idem, with 6 jars 2. 10. 0 3. Id. d Cascade Battery with Mach Commutating Device for put ting the Leyden jars in parallel also. Figure (M. P. 10th edn.. IV. 1, Fig. 20S; it"1 edn.. III. Fig. 215). with '•'> jars. List No. £ - i d c in, with <; jar>. List No. 60,596 16 4.0.0 60,599 16 6.0.0 60,597 26 6. 10. 0 60,600 L'fi 10. 0. 0 60,598 40 cm liiuli 9.0.0 60,601 Iti cm high 13. 10. 0 Cl. 2178, L'lT'.l. 2180, 21808. No. 60612. Condensers. 833 60 611. 1 : 8. 60 608. 1 : 5. 60 612. 1 : 7. 60 613. 1 : 6. Cascade Battery with commutating device, with 9 jars. List No. 60,602 60,603 16 26 £ 8. 0. 0 13. 0. 0 60,604 40 cm high 17. 10. 0 60,605. Lane's Measuring Jar, with 1 jar, on iron base (M. P. 10th edn., IV, 1, Fig. 209; 9th edn., Ill, Fig. 199) 60,606. - - idem, with micrometer adjustment, Figure 60.607. - - idem, with 2 jars, Figure (W. D. Fig. 469 [444]), can also be used for the Knochenhauer-v. Oettingen Experiment for showing the oscillating discharge .... 60.608. Condenser (Weinhold's), Figure (W. D. Fig. 459 [434]), for accumulation experi- ments. Diameter of metal plates: 21 cm, on glass pillar and base, with elder pith pendu- lums and a copper- and zinc-strip for galvanic electricity 60.609. --idem, as modified by Prof. Motz, with 1 ball underneath and 2 balls above Condensers, as suggested by Bruno Kolbe: see No. 60,319 on p. 812 (£ 1. 8. 0) and No. 60,326 on p. 813 (£ 2. 5. 0). 60.611. Condenser, as suggested by Kohlrausch, Figure (M. P. 10th edn., IV, 1, Fig. 185; 9th edn., Ill, Fig. 198), with round plates of 160 mm universally adjustable and pris- matic guide 60.612. - - i d e m, F i g u r e, with Micrometer Adjustment for the plate distance . . . . Cl. 2186, 2187, 3855, 2188. £ s. d. 1. 0.0 1.14.0 1. 4.0 1.10.0 1. 10. 0 4. 0.0 5. 0.0 53 834 Static Electricity. No. 60613- 60 614 A. 60 614 B. 60 620. 2 : 5. 60 623. 1 : 5. 60.613. Condenser, as No. 60,611, very massive pattern, Figure on p. 833, without micro- £ s- d. meter adjustment for the plate distance 6. 10. 0 60.614. Cylindrical Condenser, as suggested by Gerdium, Pigs. A and B, permitting of a measurable variation of capacity between 20 and 500 cm (Ztschr. f. d. phys. u. chem. U. 18, p. 291; M. P. 10th edn., IV, 1, Figs. 186 and 187) '. 7. 0. 0 60.615. — idem, with Certificate of Calibration of the Physikalisch-Technische Eeichs- anstalt 8. 5. 0 60.620. Spark Micrometer, as suggested by Eiess, Figure (M. P. 9th edn., Ill, Fig. 202), comprising 2 metal spheres on glass pillars, 1 of which can be adjusted by a micrometer screw in a graduated .slider 2.10.0 60.621. Discharger, simple, with ebonite handle 0. 4. 0 60.622. - - idem, with 2 ebonite handles and knuckle joint, Figure (Gan.-Man. Fig. 655; Gan.-Eein. Fig. 761) 0. 8. 0 60.623. -- idem, with 1 glass handle and knuckle joint, span 35 cm. Figure . , . o. 10. 0 60.624. Discharger, as suggested by Eiess, Figure (W. D., Fig. 468 [443]; Gan.-Eein., Fig. 772), for Leyden jar batteries, on iron base 1. 0. 0 Cl. 5678, .1077, 2182, 2181,2183. No. GO 633. Condensers, Dischargers 835 60 627. 1 : 6. 60 628. 1 : 10. 60 633. 1 : 8. 60.625. Henley's Discharger, Figure (W. D. Fig. 466 [441]) 60.626. - - idem, with interchangeable zinc balls specially given in 60.627. Franklin's Plate, Figure (M. P. 10th edn., IV, 1, Figs. 178 and 179; 9th edn., Ill, Figs. 193 and 194; Gan.-Rein. Fig. 764), of glass, on insulating base and with suspended pendulum 60.628. Franklin's Fulminating Plate, Figure (M. P. 9th edn., Ill, Fig. 237), with a connected coating on one side and a cut out coating on the other 60.629. Rosetti's Fulminating Plate, Figure (W. D. Fig. 460 [435]), with stand . . . 60.630. Glass Slab, with connected coating, for using Eosetti's Fulminating Plate as a Frank- lin Plate 60.631. Glass Slab, with cut out coating, for using Eosetti's Fulminating Plate as a Franklin Fulminating Plate 60.632. Tower with Lightning Conductor, Figure, for igniting ether 60.633. Apparatus for Explaining the Action of the Lightning Conductor, as suggested by Harris, Figure Cl. 2184, 5752, 2185, 2192, 2189,2190,2193. £ S. d. 1. 0.0 1. 2.0 0.15.0 0.18.0 0. 18. 0 0. 3.0 0. 3.0 0.10.0 2. 0.0 53* 836 Static Electricity. Nil. 60634 — 60 634. 1 : 6. 60 635. 1 : 8. 60640. 1 : 10. 60637. 1:16. 60 639. B. a. 8.0 60.634. House with Tower and Lightning Conductor, Figure 2. A small vessel, containing spirit, is placed in the tower and the sheet iron vessel placed in the house is filled with a mixture of house gas and airi and well corked. A charged Leyden Jar is placed in the neighbourhood of the sphere of the lightning conductor and discharged. The spirit- and the gas-mixture are then ignited; the former commences to burn and the latter forces the stopper out with a bang; the roof of the house is forced out and the walls collapse. 60.635. Aluminium Leaf Electroscope, as suggested by Saussure, for Atmospheric Electricity, Figure, with ivory scale and brass conducting rod, 70 cm higli ; the base can be detached (Gan.-Man. Fig. 871; Gan.-Eein. Fig. 1043) 1. 10. o Portable Electrometer and Flame Collector, as suggested by Exner : see Nos. 60,191 and 60,191 a on p. 801. Electrometer for Atmospheric Electricity, as suggested by Bruno Kolbe: see No. 60,338 on p. 814. 60.637. Leyden Jar (Lodge's), Figure, with elder pith pendulums on both coatings (Lot! in . Neueste Anschauungen iiber Elektrizitat [Modern Views of Electricity], German by Wachsnnith, Leipzig, 1896, Fig. 9 d) 1. o. o 60.638. Hydraulic Model of a Lodge Leyden Jar, Figure (loo. cit. Fig. 12) 4. 0. o By the aid of this model all phenomena attendant on the charging and discharging of Leyden .lars and the analogous mechanical actions can be clearly explained. A rubber bellows represents the dielectric, and the inner space of the rubber bellows, which is tilled with water, corresponds to the internal coating, while the intermediate space between the rubber bellows and the glass bulb visible in the illustration (which, as well as the entire apparatus, is filled with water) represents the. outer coating. The two elder pith pendulums of Apparatus No. (in.ti.'JT are represented by pressure gauges and the source of electricity by a water pump. •. [_"; ^ 60.639. Apparatus for showing Electric Constriction (change of volume of a l.rvilrii ,Iar when charged), as suggested by IMitor, Figure (Fr. phys. Teohn. II, 1, p. 100) .... 1. .">.<> The internal coating is represented by the liquid in A. and the outer coating by the liquid be- tween A and B. The two conducting liquids in Aa and lib are electrified by opposite kinds of electri- CI 4IMIS, 1MIII 'il: No. 60 644. Oscillatory Discharges. 837 60643. 1 : 10. 60644. city when the cocks R and R' are closed. The liquid rises in T and falls in T. After discharge the difference in level disappears suddenly to the amount corresponding to the residuum. d. 60,640. Hydraulic Analogon of the oscillatory discharge of a Leyden Jar, Figure (Gan.- Eein. Fig. 786) ' 1. 0. 0 60.641. Apparatus for Demonstrating the Oscillatory Character of Leyden Jar Discharges, Figure A sheet of cardboard is rapidly passed by the points of a discharger. Tne secondary coil of an induction coil is connected up at the points, the interrupter of this induction coil being short circuited and replaced by the interrupter fitted on the apparatus, and the latter interrupter interrupting the current at the moment the cardboard sheet begins its motion. A more or less narrow row of holes is produced on the cardboard strips according as whether a large or small capacity is switched on to the points of the discharger. 60.642. Lens Disc, as suggested by Boys, for the same purpose, Figure An accurately balanced metal disc carries 6 lenses, of which each two are at the same distance from the axis. Each of these pairs is therefore at a different distance from the axis. If the axis is set rotating quickly and the image of a spark projected on to a screen by the three pairs of lenses the result is a concentric ring of light in which the oscillations can be plainly seen. 60.643. --idem, Figure, with protecting box, D. C. motor for 65, 110 — 125 or 220 to 240 volts, current regulator, spark gap and screen mounted on a board Oscillation Analysing Apparatus, as suggested by Grimsehl: see Section on Mechanics. Wave Tube, as suggested by Maxwell, for demonstrating the charge and discharge from a Mechanical Point of view: see Section on Mechanics. 60.644. Apparatus (Lippmann's), Figure, for showing that the discharge of a Leyden Jar can produce mechanical motion and that by the same motion the Jar can again receive a charge (Fr. phys. Techn. II, 1, Fig. 187; Gan.-Man. Fig. 668) Cl. 5281, 5353, 5378, 5605. 4. 10. 0 4. 0.0 12. 0.0 3. 0. 0 838 Static Electricity. No. 60 645 — 60 645. 1 : 8. 60 646. 1 : 8. 60 648. 1 : 6. 60 649. 1 : 5. 60 651. 1 : 4. 60 652. 1 : 4. 60.645. Apparatus for approximately determining Dielectric Constants, as suggested by Mach, £ s. <\. Figure (M. P. 10ttt edn., IV, 1, Fig. 212; 9th edn., Ill, Fig. 212) 2. 6. 0 60.646. 2 Lodge Leyden Jars, Figure, for demonstrating Electric Resonance (Ztschr. f. (1. phys. u. chem. U. 3, p. 249), 16 cm-high 1. 6. <> One of the jars is provided with a closing wire which contains a spark gap bounded by 2 brass spheres; the other contains a fully closed circuit, which, however, is variable along its length by a sliding piece of wire. In addition, the inner coating of this latter jar is connected to the outer coating by a closing circuit interrupted only by a small spark gap. Both jars are placed alongside each other in such manner, that the closing circuits run parallel to each other (not as shown in the above figure). If now the first jar is excited with the fixed circuit by means of an induction apparatus, the second jar is also discharged at each passage of the spark by the action of resonance, assuming, of course, that the sliding contact occupies the correct position. Not too slight a motion of the sliding contact disturbs the resonance and stops the secondary discharge. Induction is also avoided by interposing a metal screen between the two jars; glass plates or wood screens have, on the other hand, no influence, j 60.647. — idem, 26 cm high .1.16.0 60,648. Indicator (Discharge Tube) (Noack's), Figure, for demonstrating Resonance Vibrations with the apparatus No. 60,646 and 60,647 (Ztschr. f. d. phys. u. chem. U. 15. p. 95) The indicator consists of an angular shaped Geissler tube which is fixed to the Lodge Jar with threads instead of the spark gap, in such manner that the tinfoil coatings on both ends make good contact with the metal parts of the jars. The tube is rendered luminous with each discharge. 0. 4. 0 60,649. Apparatus, as suggested by Puccianti, Figure, for the projection lantern (cf. M P. 10lh edn., IV, 1, 'p. 272) 0.16.0 A is a glass tube filled with cotton wool, this tube (icing continued as a capillary B. If air bubbles are then passed through A into the vessel filled with petroleum, the bubbles are repelled by the metal sphere P when this is electrified, equally so whether the electricity is positive or negative. 60,650. Rubber Bellows for above 0. 4.0 0. is. o o.o 60,65 1 . Hauy's Apparatus for investigating the Electricity produced in Minerals by Temperat urc- clianges or by 'Pressure, Figure, for fluorspar and tourmaline, with insulating stand 60.652. Kundt's Pyro-Electric Apparatus, Figure (Wiedem. Annul. 20, p. 592, 1883; 2s. p. 145, 1886; Chwolson, IV, 1, p. 253) 2. Cl. 5685, 2195, 2196,5025.2058,5624. No. 60684. Voltaic Electricity. Section 1: Galvanic Sources of Supply. 839 60 682. 1 : 2. 60 680. 1 : 5. 60 684. 1 : 6. 60 683. 1 : 4. Voltaic Electricity. Section I: Galvanic Sources of Current. Apparatus for demonstrating Potential Drop along a Conductor traversed by a Current gene- £ »• d. rated by means of an Influence Machine or an Electric Machine: see Nos. 60,541 and 60,542 on p. 826. 60.680. Bow-shaped Joint of Copper and Zinc, for Galvani's Experiment on the frog's leg, Figure (M. P. 10th edn., IV, 1, p. 315; 9th edn., Ill, p. 326; Gan.-Man. Fig. 690; Gan.-Eein. Fig. 802) 0. 3. 0 Accessories for the Voltaic Fundamental Experiments as suggested by Noack. (Ztschr. z. Ford. d. phys. U. 1885, p. 177, cf. also Gan.-Man., p. 757.) 60.681. 2 Zinc Plates, 80 mm diameter, quite plane, 1 varnished on one side, the other metallic; 2 similar Copper Plates, 2 Handles for these plates ; 1 Flexible, Circular Copper Strip and 1 Zinc Strip, with ebonite handles; 1 Mica Disc, 160 mm diameter, and an 80 mm Cloth Disc. As regards an electrometer for No. 60,681 we can recommend No. 60,704, or, better still, No. 60,705. 60.682. 3 Copper and 3 Zinc Plates and 2 insulating handles for the Fundamental Voltaic Ex- periment, as suggested by Grimsehl, Figure, for use with Grimsehl Electrometer No. 60,202, or any other sensitive leaf electrometer (M. P. 10th edn., IV, 1, p. 320). 2 Copper Plates and 1 Zinc Plate are lacquered, the remaining plates being bare. . 1.10.0 60.683. Lead Base, Copper and Zinc Strips, Leather Disc and Beaker, for carrying out the experiments as in Fig. 60,683 with plates 60,682 (M. P. 10th edn., IV, 1, Fig. 288) . 1. 0. 0 60.684. Volta's Pair of Plates with magnetic needle, Figure i 0.-16. 0 1. 8.0 Cl. 3456, 5683. 5561, 56S1. 840 Voltaic Electricity. Section 1: Galvanic Sources of Current. No. 60 KH~> - 60685 — 60688. 1 : 5 — 1 : 12 60 693. 1 : 8. 60 703. 1 : 5. 60734. 1:5. Volta's Pile, Figure, of copper and zinc plates with felt between, insulated with ebonite (Gan.-Man., Fig. 687; Gan.-Eein. Fig. 806). List No. 60,685 60,686 60,687 60,688 No. of pairs of Plates 20 30 40 50 Diameter of Plates 40 50 60 60 mm £ 1. 0. 0 1. 10. 0 2. 0. 0 3. 0. 0 Zambonic Pile, Figure, of gold and silver paper, in glass tube with terminals at the poles. List No. 60,689 60,690 60,691 60,692 60,693 60,694 No. of pairs of Plates 1000 2000 3000 4000 5000 6000 Diameter of Plates 28 28 35 35 40 50 mm £ 1.4.0 1.10.0 1.16.0 2.5.0 3.10.0 5.0.0 - i d e in, open, the discs strung on ebonite rod, with terminals at the ends. The internal resistance can be regulated within certain limits by pressing the discs together by means of a screw device. Any pressures can be taken off by the aid of a needle with terminal let into the pile at the side. List No. 60,695 60,696 60,697 60,698 60,699 60,700 No. of pairs of Plates 1000 2000 3000 4000 5000 6000 Diameter of Plates 28 28 .'55 .'.."> 40 50 mm £ 0. 18. 0 1. 4. 0 1. 10. 0 1. 16. 0 3. 0. 0 4. 0. 0 60,257. Pile Electrometer (Bohnenberger-Fechner's), Figure . . . . 60,702. — idem (Bennet's), Figure (M. P. 9th edn., Ill, Fig. 292) 60.703. Pile Electrometer (/tschr. z. Ford. d. phys. I".. 18S6. p. 11!>), F i g u re. for objective demonstration, with degree graduation on glass, pile conducted off in the centre . . 60.704. -- idem, Figure, with open piles, variable sensitivity 2. 15.0 2. 0.0 3. 5.0 3.15.0 Cl. 219S, 2200, 2201, 2199, 391, 392. No. 60 710. Voltaic Piles, Electrometers. 841 60 708. 60 705. 60 709. 1 : 4. 60 710. 1 : 6. 60,705. Electrometer (HankePs) (M. P. 10th edn., IV, 1, Fig. 257), Figure, amber-insulated 60,258. Water-Battery for charging Quadrant Electrometers and the Hankel Electrometer, Figure 60,258 on p. 808, 144 copper-zinc cells on ebonite stand (W. D. p. 759 [700]) 60.707. Water Battery (Rowland's), 400 cells (Ztschr. f. d. phys. u. chem. U. 1, p. 120; W. D. p. 760) 60.708. Electrometer with Quartz Fibres and microscopic reading, as suggested by Prof. E. Wichert, Figure, very sensitive and provided with excellent insulation. In case 60,709. Discharge Electrometer (Weinhold's), Figure (W. D., Fig. 506 [479]) 60,710. Quadrant Electrometer (Thomson-Mascart's), Figure (M. P. 10th edn., IV, 1, Fig. 253; 9th edn., Ill, Fig. 180), without replenisher, with adjustable bifilar suspension, closed by metal cylinder, Maxwell vane, quadrants heavily gilt, excellent amber- insulation . £ s. d. 9. 10. 0 3. 0.0 3. 5.0 9.10.0 1. 7.0 11. 0. 0 Cl. 5688, 5691, 2204, 4094. 842 Voltaic Electricity. Section 1: Galvanic Sources of Current. Xo. 60711 — 60711. 1 : 5. 60719. 1 : G. 60720. 1 : 3. 60,711. Quadrant Electrometer (Thomson-Weinhold's), Figure (W. 1). Figs. 499—503 i * «1- [472 — 476]; Gan.-Man., Fig. 649), with replenisher; Maxwell vane (M. P. 10th edn., IV, 1, Fig. 254; 9th edn., Ill, Fig. 182), all internal parts heavily gilt; with mirror, and arranged for subjective as well as objective reading, with excellent amber insulation IL'. o. o (Hi. 7 12. Replenisher (Thomson's), for explaining the mode of action and for practical use, Figure (cf. Fr. phys. Techn. II, 1, Fig. 65) Accessories for Quadrant Electrometers Nos. 60710 and 60711. 60,713. Wall Bracket and Wall Arm" for a paraffin, gas or incandescent lam]) 1. 4. 0 (i. is. o lid, 714. Protecting Case for Quadrant Electrometers Nos. lio.710 and 60,711 0.10. The protecting case is made of pasteboard covered with calico, ocing suspended from a ceiling pulley. When the electrometer is in use, the case is raised up, and v lien the' electrometer is not in use. the case protects it entirely from dust. The electrometer can thus always maintain one. position. Cl. 5255. 33, 2206, 2214, 220S. No. 60724. Quadrant Electrometers. 843 60 721. 1 = 6. 60 723. 1 : 6. 60 724. 1 : 9. 60,715. Scale for Objective Reading, 2 m long, of /paper, with wood frame and legs, divided £ s. d. every 5 cm 0. 8. 0 (in. 710. Paraffin Lamp with slotted chimney, on raised base 0. 8. 0 60.717. Argand or Auer Burner with slotted chimney, on adjustabel raised base 0.15.0 60.718. Electric Incandescent Lamp, on stand and with shielding cylinder, Figure, for quadrant electrometers and mirror galvanometers 0. 18. 0 The glow lamp is of the long filament type. The voltage should be given when ordering. If this is not stated we supply 110-volt lamps. (in. 719. Demonstration Quadrant Electrometer, Figure, simple pattern, in wood house, well suited for teaching purposes (Stewart & Gee, Practical Physics, Fig. 114) ... 3. 4.0 00,720. Quadrant Electrometer (Dolezalek's), Figure (Ztschr. fur Instrumentenkunde, 21, p. 345), for measuring small potential differences .of approx. 1 to 0.001 volt .... 8. 0. 0 The needle is of a very light type, its weight with mirror being only 0.2 gram. It is suspended from a quartz fibre rendered conductive by hygroscopic salts and is so formed as to be self-damping, j It is charged with 50 to 200 volts. 00,721. - - idem, modified by Wien, Figure, with tall base and platinum point, in order to enable the electrometer to be charged from underneath, also with calcium chloride desiccator; for measuring small potential differences of approx. 1 to 0.001 volt; with amber insulation and case of Quartz Fibres 10. 0. 0 60,722. Case of Quartz Fibres for Nos. 60,720 and 60,721 0. 5. 0 iid.723. Quadrant Electrometer (Elster & Geitel's), Figure, with first quality insulation, also suitable for investigating radio-active substances (Wiedem. Ann. 64, p. 680) . . 12. 10. 0 The damping, needle adjustment, torsion of the suspension device and the drying arrangement (with sodium) can be regulated independently of each other. The instrument has variable sensitivity. — A deflection of 1000 scale divisions can be attained with 1 volt. (io.724. Cylindrical Quadrant Electrometer (Edelmann's), Figure, with cast zinc wall bracket (Fr. phys. Techn. II, 1, p. 98) 14.10.0 The vane and quadrants consist of elongated cylindrical sections, the vane being adjusted by ' a small magnet. Raw silk fibre suspension; vane charged by water battery Nos. 60,706 or 60,707. The instrument is very sensitive and easy to manipulate. For Dry Piles Jor Charging Needles of Quadrant Electrometers see Nos. 60,689 to 60,700. Cl. 3951, 5201, 5776. 844 Voltaic Electricity. Section 1: Galvanic Sources of Current. Xo. 60 72 J — 60 725 A. 1 : 8. 60 725 B. 1:4. 60727. 1:6. 60 726. 1 : 6. 60729. 1:4. 60.725. Mirror Electrometer for High Potentials, as suggested by Heydweiler, Figs. A and B (Ztschr. f. d. phys. u. chem. U. 6, p. 255; Ztschr. fur Instrumentenkunde 12, p. 377; Elektrotechnische Ztschr. 1893, p. 29), with 2 bifilar suspensions, easily inter- ' changeable, for measurements of 3000 to 27,000 volts and of 6000 to 50,000 volts. . The instrument is essentially a torsion balance and has the advantage that the potentials to be measured are nearly proportional to the square root of the scale readings. The results are very accurate. The electrometer has a good damping arrangement. Subjective and Objective Reading Devices for Electrometers Nos. 60719 to 60725: see Mirror Galvanometers. 60.726. Absolute Electrometer (Electrometer Balance with protecting ring condenser), as suggested by Thomson-Kirchhoff , Figure, without balance The lower of two circular plane parallel condenser plates of gilt brass is fixed in an insulating material, while the upper is suspended on a sensitive balance in the manner of a balance pan. The balance suitable for the above is No. 51,542 on p. 234. Standard Cells. 60.727. Standard Copper-Zinc Cell (Weinhold's), Figure (\V. I), p. 752 [694]) 10. 0. 0 60.728. Standard Cell (Kittler's), with chemically pure copper and zinc plates, in polished oak case with handles Sulphuric acid of 1.075 specific gravity at 80° C. and a solution of copper-sulphate of 1.19 sp. gravity is used for charging. E. M. F. 1.182 v. at 15.5° C. 60.729. Standard Cell (Fleeming's), Figure (M. P. 9th edn., Ill, Fig. 304; Kolbe-Skellon, Introduction to Electricity, Part II, Fig. 113; Can. -Man. Fig. 726) 60.730. Clark Standard Cell, self-filling type as suggested by Ostwald, Figure, with pole terminals < 1.2211, 2212, 2213, S850. 16. 0. d 0.10. 0 2.10. (i 1.1-2.0 0. 1. 0 5793 ». No. 60 738. Standard Cells, Demonstration Cells. 845 60730. 1:3. 60 731. 1 : 3. 60732. 1:2. 60 734. 1 : 4. 60737. 1:3. 60 737 a. 1:6. 60738. 1:6. 60.731. Standard Cell (Clark's), Figure, prepared in accordance with the instructions £ s. d. of the Eeichsanstalt, with Test Certificate. (M. P. 10th edn., IV, 1, Fig. 489; Gan.-Eein., Fig. 817) 2. 0. 0 60.732. Standard Cell (Weston's), Figure, with a not fully concentrated solution of cadmium sulphate, Original Weston Standard Cell, with low internal resistance, without temperature coefficient, usual type for precision measurements; average value of e. m. f. 1.0190 volt, (M. P. 10th edn., IV, 1, Fig. 490) 2. 0. 0 60.733. - - idem, double form (2 separate cells in one case) 3. 0. 0 60.734. International Weston Standard Cell, Figure, prepared in accordance with the specification of the International Congress of Electrical Units and Standards, London, 1908, with saturated cadmium sulphate solution with excess of cadmium sulphate crystals; temperature coefficient: 0.004 per cent per degree, in case suitable for petroleum bath; without thermometer 1.15.0 60.735. - - idem, double form (2 separate cells in one case) 2.15.0 60.736. Thermometer, suitable for above 0. 5. 0 The testing, verification and determination of temperature coefficient of cells Nos. 60,732 to 60,735 by the Eeichsanstalt are carried out by the Eeichsanstalt at cus- tomers' expense. Galvanic Demonstration-Cells. 60.737. Zinc-Copper Cell with separate carbon electrode, Figure (Gan.-Man. Fig. 688; Gan.-Eein. Fig. 803). Dilute sulphuric acid 1 : 10 is used for charging 0. 3. 0 60,737 a. Demonstration Cell, Figure, for use with Holtz Clamps, without the latter (see Xo. 60,172, p. 799), with 2 copper plates, 1 zinc and 1 iron plate 0. 8. 0 60.738. Small Voltaic Cell, as suggested by Kolbe, Figure (Kolbe-Skellon, Introduction to Electricity, Part II, Fig. 85), on wood board, for charging with dilute sulphuric acid (1 : 10) 0. 2. 0 01.2222, 2220, 2219. 34', 2221, 5760, 579»>-. 846 Voltaic Electricity. Section 1: Galvanic Sources of Current. No. 60739 — 60 741. 1 : 4. 60 740. 3 : 4. 60743. 1 : 3. 60 744. 1:5 60.739. Small Projection Cell (Kolbe's), Figure (Kolbe-Skcllon, Introduction to Elec- tricity, Part II, Fig. 87), for charging with dilute sulphuric acid (1 : 10) 60.740. Small Constant Cell, as suggested by Kolbe (Kolbe-Skellon, Introduction to Elec- tricity, Part II, Fig. 92), on wood base, Figure The cell is a sin nil U-shaped Daniell cell, the centre part of which — at the lie-nil — is pliifij:<'. (I 0. 16.0 7. 10.0 0. (i. I) 5793 b, No. 60 752. Demonstration Cells. 847 60745. 1 : 4.j 60748. 1 : 5. 60747 and 60748. 1 : 8. 60750. 1 : 5. 60751. 60752. 1 : 4. 60.744. Zinc-Copper Cell, with gas generating tube, Figure, including stand and seat (M. P. 10th edn., IV, 1, Fig. 299) 60.745. Connecting Piece with platinum foil, for proving the heating of the external circuit, Figure; price does not include the Holtz Clamps illustrated, No. 60,172 (M. P. 10th edn., IV, "1, Fig. 301). The cell most suitable for this is No. 60,746 60.746. Wollaston Cell, Figure, with simple carbon plate and U-shaped zinc plate . . 60.747. Trough Cell (Kolbe's), Figure, with, however, only 1 each zinc and carbon plate, for demonstrating the influence of internal resistance (Kolbe-Skellon, Introduction to Electricity, Part II, Figs. 120 and 121) 60.748. -- idem, with separating wall and a pair of extra plates, F i g .u r e 60.749. Folding Cell (Grimsehl's) (Ztschr. f. d. phys. u. chem. U. 8, 1894, p. 209, Fig. 1). 60.750. Zinc-Copper Cell, as suggested by Friedr. C. G. Miiller, F i g u r e, for demonstrating the action of the polarisers (M. T. Fig. 206) 60.751. Apparatus for demonstrating the E. M. F. at the limits of 2 electrolytes, Figure (Fr. phys. Techn. II, 1, Fig. 503) 60.752. Reduction-Oxidation Cells, Figure (Liipke, Eiidorffs Grundrifi der Chemie, 12th edn., 1902, p. 286) The two cells of the series contain each 1 platinum electrode connected by wire leads to a galvano- meter. 1 cell is charged with a solution of stannic chloride, the other one as well as the syphon connecting the cells containing an acidulated solution of common salt. If a crystal of mercuric chloride is placed on the electrode of the last-named cell, the galvanoscope needle deflects in such manner that this electrode appears as a positive pole. £ s. d. 0.12.0 0. 3.0 0. 6.0 1.10.0 2. 0.0 0.15.0 0. 8.0 0. 4.0 1. 5.0 Cl. 5682, 3504, 3S74, 5010, 2480, 3704. 848 Voltaic Electricity. Section 1 : Galvanic Sources of Current. No. 60753 — 1 fflWa 3 60 753. 60754 — 60756. 1:5—1:6. 60 759 A. 1:4. 60 758 a. 1:3. 60 759 B. 1:9. 60,753. Apparatus as suggested by F. Dolezalek and F. Kriiger, Figure, for demonstrating the current flowing through a circuit consisting of liquids only (M. P. 10th edn., IV, 1, Fig. 495 b) The annular vessel is half filled with a 35% solution of sulphuric acid, the surface of this vessel being covered with cork discs. A 30% solution of sodium acetate is introduced above these cork discs, at one side, up to 20 mm, the other side containing a 20% solution of lithiumchloride up to the upper edge of the ring. If the circuit so prepared is placed above the small system of magnets suspended from the stand (the deflections being observed by means of luminous pointer and scale), a deflection of the luminous index is obtained. If the ring is rotated the pointer moves to the other side. If the solution is mixed by shaking no deflection is obtained. Galvanic Cells for Ordinary Use. The prices of all cells, with the exception of Nos. 60,785—60,788 are exclusive of electrolyte. Bunsen Cell, Figure, with heavily amalgamated zinc cylinder, porous pot and natural carbon plate, with zinc and carbon pole terminals (Gan.-Man. Fig. 723; Gan.-Kcin. Fig. 813). List No. 60,754 60,755 60,756 Length of Carbon Plato 160 210 260 mm £ 0. 7. 0 0. 8. 0 0. 10. 0 Electrolyte: /inr Cylinder in dilute sulphuric arid. l.Oli sp. gr. (about .~>u rrm II,S04 to 1 liter water), carbon plate in concentrated nitric acid. - idem, with tall and wide glass vessel and ebonite cross on bottom, for continuous working, charging of accumulators, etc. List No. 60,757 60,758 Length of Carbon Plate 210 2<>U mm £ 0. 10. 0 0. 12. 0 60,758 a. Celluloid Top for Bunsen Cells Nos. iio,7:>7 ami ti(i.7.")S (M. T. Fig. 172), Figure 0. Cl. 5679, 5781'-, 2^26, 2227, 4517. No. 60784. Cells for ordinary use. 849 60763. 1:6. 60765. 1:6. Grove Cell, F i g. 60,759 A, with zinc cylinder and S-shaped platinum sheet. List No. 60,759 60,760 60,761 Length and width of platinum sheet 160x60 100x50 60x40 mm £ 2.0.0 1.4.0 0.16.0 Fig. B shows a battery consisting of 60 cells. Electrolyte: as in Bunsen Cell. Daniell Cells, with copper cylinder and zinc cross, Figure (Gan.-Eein., Fig. 809) : List No. 60,762 60,763 60,764 Height of glass 160 200 250 mm £ 0.5.0 0.6.6 0.8.0 Electrolyte: porous pot with zinc cross in dilute sulphuric acid 1.06 sp. gr. (about 50 com pure sulphuric acid to 1 litre water); copper cylinder in saturated solution of sulphate of copper (about 1 part crystallised copper sulphate to 3 parts water). Cupron Cells, Figure, improved Lelande Cell, regenerable (Cupric oxide-alkali-zinc) ; ter- minal voltage per cell about 0.8 volts. Type I II III IV List No. 60,765 60,766 60,767 60,768 Length X Width x Height 190x55x170 190x75x240 200x110x280 250x140 370 mm Normal Current Approx. capacity Caustic Soda with 1%\ Sodium Hyposulphite) Water £ 1—2 50 0.2 2—4 100 0.4 4—8 200 0.8 8 — 16 amps. 400 amp.-hrs. I 60,770 0.0.4 II 60,771 0.0.8 III 60,772 0.0.8 IV 60,773 0. 1. 10 60,774 0.3.0 60,775 0.5.0 60,776 0.5.0 60,777 0.8.0 1.6 kg 1.2 2.3 4.4 7 litres 0.5.0 0.9.0 0.16.0 1.7.0 60,769. Caustic Soda in sheet iron boxes (with 1% soda hyposulphite) 1 kg Spare Zinc Plate for Type . . List No. £ Spare Cupric Oxide Plate. List No. £ Exact instructions for use are supplied. Smee Cells, consisting of a platinised silver plate between two zinc plates. List No. 60,778 60,779 Height 160 200 mm £ 0. 18. 0 1. 4. 0 Electrolyte: dilute sulphuric acid 1.06 sp. gr. (about 50 ccm pure sulphuric acid to 1 litre water). Bottle Cell (Grenet's), Figure, with 2 carbon plates and 1 zinc plate (Gan.-Man., Fig. 724; Gan.-Eein., Fig. 815). List No. 60,780 60,781 60,782 60,783 Capacity 1/t V2 1 1V2 litres £ 0.2.6 0.3:6 0.5.0 0.7.0 Electrolyte: 02 grams powdered potassium bichromate, or better still, 81 grams sodium bichromate (K2Cr2O7 or N'a., ( V, ()-) are worked up together with 94 ccm of pure sulphuric acid to a smooth paste, in a dish. Before hardening 900 ccm water should be added until everything is dissolved. £ s. d. 0. 0. 9 0().7S4. Large Bottle Cell, 340 mm high, with Electrolyte: as in Xos. 60,780 — 60,783. carbon and 2 zinc plates; very powerful 1. 2. 0 Cl. 5S22, 57SO:1, .17.SU-. 54 850 Voltaic Electricity. Section 1: Primary Batteries. No. 1:1 60 785. 1 : 6. 60 788. 1 : 7. 60 789. 1 : 6. 60791. 1:5. Leclanche Cells, Figure, with manganese dioxide cylinder, zinc rod and electrolyte of sal-ammoniac; used formerly chiefly for house telegraphy and telephony (Gan.-M;m., Fig. 725; Gan.-Kein., Fig. 818). List No. 60,785 60,786 Height 160 250 mm £ 0. 2. 6 0. 3. 6 Electrolyte: at a height of 16 cm 50 — 60 grams and at 25 cm 100 grams of sal-ammoniac are dissolved in water and this is introduced to about 3 cm from the upper edge. Cells (Fleischer's), Figure, chiefly used at the present time for house telegraphy and telephony; it is also very practicable for physical purposes with feeble currents. List No. 60,787 60,788 Height 160 250 mm £ 0. 3. 0 0. 4. 0 Electrolyte: as No. 60,785 and 60,786. Meidinger's Cell, current. Figure, balloon cell, chiefly used for telegraphy with closed circuit List No. Total Height £ 60,789 240 0.3.6 60,790 300 mm 0.5.6 Helleson Dry Cells, rements, etc. F i g u r e, List NO. Total height mm Mase nun Approx. internal resistance ohms 60,797 122 57x57 0.30 0. 2. 0 60,798 155 63x63 0. 2. 6 60,799 180 60,800 L96 76x76 100 x 100 0.20 0.15 0.3.0 0.4.6 This cell can be stoivd for any length of time before bring put in use and is only ready for use when' filled with water alter screwing off t lie ebonite closing cap. When filled I lie cap should be screwed down firmly again. In addition the, remarks re the Ilelleson I >r\ Cell apply here also. s. d. Electrolyte: the large glass is half filled with water in which is dissolved 20 or 50 grams respec- tively of magnesium sulphate so that when the globe is inserted the zinc cylinder is entirely immersed in water. The globe should be filled with 650 or 1500 grams respectively of copper sulphate in pieces as large as hazel nuts and should be closed with the plug and glass tube. 60,791. Cell as suggested by ('allaud-Kriiger, Figure, for telegraphy and closed circuit current installations, 160 mm high (Gan.-Man., Fig. 722; Gan.-Eein., Fig. 811) . . . Electrolyte: the cell is filled with water in which 15 grams magnesium sulphate is dissolved, with the subsequent addition of 60 — 75 grams (not more) copper sidphate in small pieces. According as how the cell is used enough copper sulphate should be added until the lead plate rests in a bluish-green coloured stratum. 0. 3. 6 well adapted, for telegraph and telephone work, bells, mcasu- List No. 60,792 60,793 60,794 60,795 60,796 eight, mm 83 122 155 180 195 Base mm 32x32 57 X57 63x63 76x76 100x100 mce ohms 0.35 0.25 0.20 0.15 0.10 £ 0.1.0 0.1.7 0.2.0 0.2.9 0.4.0 The cell has an c. m. f. of approx. 1.5 volt and is characterised by great durability, high recu- perating capacity, good depolarisation, small internal resistance, hick of sensitivity id tempenitim changes, and by its good capacity. The most practical sizes are those of 155 mm and 180 mm height. Helleson Stock Cells, rechargeable dry cell; it can remain for any length of time before being used and is therefore excellently adapted for over-sea countries. Cl. .•)781:i, .r , 3505. No. i;osi-.'. Primary Batteries. 851 60 806. 1 : 9. 60795. 1 = 4. 60809. 1 Immersion Batteries for potassium bichromate electrolyte, Figure, size of plates 200 x 100 mm, the plates being raised by means of a handle on stand, with pulleys. List No. 60,801 60,802 60,803 60,804 60,805 60,806 With 6 8 10 12 16 20 cells £ 5.2.0 6.16.0 8.5.0 9.12.0 12.16.0 16.0.0 2.5 litres electrolyte as in Nr. 60,780 is necessary for one cell of this size. The carbon plates of all immersion batteries consist of natural gas carbon, the zinc plates of best quality rolled zinc. Tho immersion batteries are so arranged that the glass vessels can be easily taken out for cleaning. -idem, Figure, size of plates 180 x 90 mm; the plates are raised by means of a handle on stand, with pulleys. List No. 60,807 60,808 60,809 60,810 60,811 60,812 With 6 8 10 12 16 20 cell* £ 4.10.0 6.0.0 7.5.0 8.8.0 11.4.0 14.0.0 1.4 litre electrolyte as in NO. iiu.780 is necessary for one cell of this size. £ s. d. (Jl. 2233, 2230, 2234. 54* 852 Voltaic Electricity. Section 1: Primary Batteries. No. 60813- Si PIT* 60813. 1:10. 60 840. 1 : 8. 60 825. 1 : 9. 60820. 1:8. 60 841. 1 : 4. 60 844. Immersion Batteries, simple construction, Figure, size of plates 200 x 100 mm. Plates raised by both hands by means of two handles. List No. 60,813 ^60,814 60,815 60,816 60,817 60,818 With 2 4 6 8 10 12 cells £ 1.18.0 2.16.0 4.4.0 5.12.0 7.0.0 8.8.0 2.5 litres electrolyte as in No. 60,780 are necessary for one cell of this size. -idem, Figure, size of plates 180 x 90 mm. Plates raised by both hands by means of two handles. List No. 60,819 60,820 60,821 60,822 60,823 60,824 With 2 4 6 8 10 12 cells £ 1.14.0 2.8.0 3.12.0 4.16.0 6.0.0 7.4.0 1.4 litre electrolyte as in No. 60,780 is necessary for one cell of this size. 60,825. Immersion Battery No. 60,808 mounted ready with Multiple Commutator, Figure The multiple commutator permits of putting all 8 cells in parallel or series or in two groups of 4 cells each, or, finally, in 4 groups of 2 cells each. 60,82<;. Spare Glass Vessel for Nos. 60,801—60,806 and 60,813—60,818 60,827. — i d e m, for Xos. 60,807—60,812 and 60,819—60,824 60.828. Spare Carbon Plate for Immersion Batteries, 200xl(H» nun, for Nos. 60,801—60,806 and 60,813—60,818 60.829. -- idem, 180x90 mm, for Nos. 60,807—60,812 and Nos. 60,819—60,824 . . . 60.830. Spare Zinc Plate, 1'OOxlOO mm, for Nos. 60,801—60,806 ;md Nos. 60,813— 60,s 18 60.831. -- idem, 180x!»0 mm, for Nos. 60,8(17—60,811' :m:>:(.•.. •.'•_':!•, •.'•.':»;. Mtt, £ s. d. 9. 16. 0 0. 3. U o. 2. 0 0. 2. 6 0. 1.8 0. 2. 0 0. 1. 6 5100, No. K0851. Primary Cells, Polarising Cells. 853 60 846. 1 : 5. 60 848. 1 : 5. 60 850. 60851. 60.832. Battery of 30 small Grove Cells (platinum-zinc cells), for working a projection lantern, in carrying case • 60.833. - - idem, with 50 cells For Multiple Commutators (Pachy tropes), see Section: Current Conduction and Distribution. Electrolytes for Cells. 60.835. Copper Sulphate, crystallised per kg 60.836. Potassium Bichromate per kg 60.837. Sodium Bichromate per kg 60.838. Sal-Ammoniac, technically pure per kg 60.839. Magnesium Sulphate per kg Polarising Cells and Batteries. 60.840. Polarising Cell with platinum electrodes, Figure £ s. d. 22. 10. 0 37.10.0 60.841. Polarising Battery (Weinhold's), Figure (W. D., Fig. 527 [500]), for decomposing water by means of a single Bunsen or Grove Cell, with four small platinum cells . . 60.842. Polarising Battery (Poggendorff's) (M. P., 9lh edn., Ill, Figs. 418—420), with 4 cells and with mercury switch 60.843. Poggendorff's Switch, for 4 cells. Price without cells 60.844. Plante Cell (Secondary Cell), Figure (Gan.-Eein., Figs. 958 and 959), 26 cm high 60.845. --idem, 20 cm high 60.846. - - idem, with commutator for putting in circuit an incandescent wire while dis- charging, Figure (Gan.-Man., Fig. 830, without the cells illustrated in the book) 60.848. Grove's Gas Cell, Figure (M. P., 10th edn., IV, 1, Fig. 502; 9th edn., Ill, Fig. 422; Gan.-Eein., Fig. 957) 60.849. Gas Cell (W. D., Fig. 526 [499]) 60.850. v. Babo's Apparatus, Figure, for showing the elongation of paladium on absorbing hydrogen (Fr. phys. Techn. H, 1, Fig. 284) 60.851. Landolt's Apparatus for the same purpose, Figure, suitable for projection (Fr. phys. Techn. II, 1, Fig. 285) 0. 1.6 0. 1.9 0. 1.6 0. 1.6 0. 0. !) 1. 0.0 3. 0.0 3. 6.0 1. 4.0 1. 4.0 0.18.0 1.16.0 1. 1.0 0.15.0 1. 4.0 1. 4.0 Cl. 4950, 2265, 5016, 5023. 854 Voltaic Electricity. Section 1: Secondary Cells and Batteries. X,,. fill S.VJ 60 854. 1 : 5. 60 953 B. 1 : 8 (Ocelli*). 60 859. 1 : 0. 60878. 1 : 10. 60 855. 1 : 0. 60 953 A. 1:8(6 cells). 60 953 C. 1 : 8 (6 colls). Accumulators and Accessories. The use of Accumulators for obtaining a constant and reliable supply of current which is always ready for use cannot be too highly recommended. They are never superfluous in places where a central station is available. The charging of the accumulators is carried out either on any direct current plant, a lamp resistance being in circuit, or by the aid of a switchboard; or supposing that a direct current installation is not available, they can be charged by a thermopile; or, if this is impossible, with 3 or 4 Bunsen cells. If an alternating or a 3-phase current lighting plant is available, it is advisable to employ a rectifier. Precise instructions for the charging and manipulation of the accumulators arc supplied with each battery. As a rule the battery can be set up in the lecture table. The mean discharge voltage is about 2 volts per cell. The batteries supplied by us are excellent in their action even when not in constant use. Repairs are practically excluded if the batteries are used to some extent in an appropriate manner. C.o.sr.i1. One each Positive and Negative Accumulator Plate, for demonstration purposes, grid plates o. i. o 60.S53. - - i (1 e in, 0. 5.6 60,854. -- idem, large-surface plates. Figure (I. (i. 0 <;o.x.V>. Demonstration Accumulator, open. Figure, for taking t<> pieces, also suitable for practical purposes; capacity on 3-hour discharge, \'2 ampere-hours 0. In. n Single Accumulators for School use, Figure, portable, built into glass vessels, with terminals. Si/e I .Max. charge and discharge current Amps. 1.5 Capacity on 3-hour discharge Amp.-hrs. 4.5 ( 'apacit y on 10-hour discharge Amp.-hr. 6.7 List No. 60,856 £ 0. 5. 0 — i (I e m, built into ebonite cell. List No. £ II III IV V 4 8 12 16 12 24 36 48 L6 30 16 60 60,857 60858 60,859 60,860 0. 12. 0 0. 16. 0 1.0.0 1.4.0 60,862 60,863 60,864 60,865 0. 16. 0 1.0.0 1.5.0 1. 10. 0 Cl. .V.'()4..->si|-.'. til Si, mi No. tid-ii;'... Accumulators. 855 Batteries of Accumulators, portable, without Multiple Commutator, Figure The cells are built into glass vessels. Size II III IV V .Max. charge and discharge current) 1 O 1 £i Amps. } \2i lo Capacity when discharged for 3 hours \ Ampere hours) 12 24 36 48 Capacity when discharged for 10 hours \ Ampere hours) 15 30 45 60 List No. £ s. List No. i £ S. List No. £ s. List No. £ 8. Price of a 2-cell battery .... 60876 1. 16 60 884 2. 5 60892 2.10 60 900 3. 0 Q 77 77 77 ' 77 77 .... 60877 2. 6 60 885 3. 0 60893 3.10 60 901 4. 5 77 77 77 ' 11 11 .... 60 878 2. 18 60 886 3. 15 60894 4.10 60 902 5.10 77 77 77 " 77 77 .... 60 879 4. 0 60 887 5. 10 60895 7. 5 60 903 8.10 Q 77 77 77 ° 7? • 77 .... 60 880 5. 16 60 888 7. 10 60896 9. 0 60 904 11. 0 12 77 77 77 J--' 77 77 .... 60881 8. 0 60889 11. 0 60897 13.10 60 905 16.10 7) 77 77 J-O 77 77 .... 60 882 11. 12 60890 15. 0 60898 18. 0 60 906 22. 0 77 77 77 " 77 77 .... 60883 16. 0 60891 22. 0 60899 27. 0 60 907 33. 0 - i d e m, cells built into ebonite vessels , for purposes where the batteries are exposed to knocks during transit. Size II III IV V Max. charge and discharge current] 4 8 ¥> 16 Amps. ) Capacity when discharged for 3 hours > Ampere hours ) 12 24 36 48 Capacity when discharged for lOhours) Ampere hours} 15 30 45 60 List No. £ s. List No. £ s. List No. £ s. Lis tNo. £ s. Price of a 2-cell battery .... 60 908 2. 4 60 916 2. 10 60924 3. 0 60 932 3.12 77 77 77 " 77 77 .... 60 909 2. 18 60 917 3. 8 60925 4. 0 60 933 5. 0 4 77 77 77 fc 77 77 .... 60 910 3. 15 60 918 4. 8 60926 5.10 60 934 6.10 77 77 77 " 77 77 .... 60 911 5. 5 60 919 6. 5 60927 8. 5 60 935 9.15 77 77 .... 60 912 7. 10 60 920 8. 16 60928 11. 0 60 936 13. 0 77 77 77 *-" 77 77 .... 60 913 10. 10 60921 12. 10 60929 16.10 60 937 19.10 77 77 77 •J-" 77 77 .... 60 914 15. 0 60922 17. 12 60930 22. 0 60 938 26. 0 77 77 77 ^* 77 77 .... 60 915 21. 0 60 923 25. 0 60931 33. 0 60 939 39. 0 Batteries for School Use, with Multiple Commutator, cells Figures. Fig. A shows the front closed, Fig. with drop wall. Size Max. charge and discharge current) Amps. ) Capacity when discharged for 3 hours i Ampere hours) Capacity when discharged forlOhours \ Ampere hours) List No. Price of a 4 -cell battery .... 60946 6 „ „ .... 60947 8 „ „ .... 60 948 12 „ „ .... 60949 16 „ - „ .... 60950 24 „ 60951 in glass vessels fitted in a solid wood box, B. the same open. Fig. C shows the back 11 77 77 77 77 77 77 77 77 II Ill IV V 4 8 12 16 12 24 36 48 15 30 45 60 £ s. List No. £ S. List No. i £ s. List No. | £ s. 5 4. 18 60 952 5. 15 60 958 6. 10 60 964 7.10 7 6. 8 60 953 7. 18 60 959 9. 13 60 965 10.18 8 9. 0 60 954 10. 14 60 960 12. 4 60 966 14. 4 9 13. 8 60 955 16. 18 60 961 18. 18 60 967 21.18 3 18. 0 60 956 21. 8 60 962 24. 8 60 968 28. 8 1 26. 16 60 957 33 16 80 963 37. 16 60 969 43.16 A multiple commutator in place of the plug arrangement is somewhat more expensive to use, but it ob- riatea any short circuiting ami therefore the resultant ruination of the cells. When put in parallel and in groups the discharge currents and the. capacity are increased while the voltage available is smaller. TV' uses to which the accumulators can be put are very varied. They can be employed, e. g. for feeding th<- lamp for the mirror galvanometer, for driving an electric, motor for colour dis-s, (ieissler tubes, syrens or double syrens; for working an induction coil, etc. etc-., and their provision cannot be too highly recommended. as the teacher has always a powerful never failing source of current at his disposal. The accumulators are charged, when a heavy current supply is not available, by means of one of the thermopiles described on the following pag'-s, or by Bunscn Cells. As the thermopiles require no attention, the accumulators can be charged day and night without interruption: the consumption of gas being extremely small. For following the progress of charging it is advisable to provide a voltmeter, and for the operation of 856 Voltaic Electricity. Section 1: Galvanic Sources oJ Current. No. 60870 — 60 994. 1 : 7. 60 995. 1 : 6. 60 996 A. 1 : 12. discharging, an ammeter. In addition it is desirable to have a regulating resistance so as to be able to take off current of any current-density according to requirements. The multiple commutator permits of the cells being put in parallel for charging and putting them both in series, in groups and in parallel when discharging. For most purposes an 8-cell battery No. 60,954 at £ 10. 14. OJsize III) is sufficient. With reference to tho chiiryin.i;- of accumulators, vide Prof. Friedr. C. G. Muller's work: fiber Aufstellung und Betrieb von Akkumulatorm fin- den Schulgebrauch", Ztschr. f. d. phys. u. chem. U. 11, p. 124. Batteries for School Use, with multiple commutator. The cells are built into ebonite vessels. Size Max. charge and discharge current) Amps. } Capacity when discharged for 3 hours ) Ampere hours} Capacity when discharged for lOhours \ Ampere hours) Price of a 4-cell 6 , battery 12 16 24 Stationary Battery quoted for on application. II III IV V 4 8 12 16 12 24 36 48 15 30 45 60 List No. £ s. 60 970 5. 15 60 971 7. 13 60972 10.14 60973 15.18 60974 20.18 60975 31.16 List No. | £ s. 60976 6. 8 60 977 8. 13 60978 12. 0 60979 17.18 60980 24. 0 60981 35.16 List No. £ s. 60 982 7. 10 60983 10. 8 60984 14. 4 60985 21.18 60986 28. 8 60 987 43. 16 List No. £ s. 60 988 8. 10 60989 12. 8 60990 16. '? 4 60991 24.18 60992 32/8 60993 49.16 60,994. Battery of Accumulators, K i g u r e, consisting of 16 small accumulators in an in- £ s (1 sulated wood stand. These groups of 16 cells each can be combined in any number to form a High Voltage Battery 3. IL>. o The max. charge and discharge current of this type of accumulator is 0.6 amp., the capacity being 3.5 ampere-hours. Each cell has 1 positive and 2 negative plates. 60,995. Battery of Accumulators (Zehnder's), Figure, consist ing of 20 Cells. The Batteries can be combined in any number to form a High Voltage Battery ......... battery is supplied with formed plates. The maximum charging current is 0.06 ampere, the capacity being 0.3 — 0.7 ampere-hour according to the time of discharge; 2.5 volts per cell should be taken as the final voltage when charging. Instructions for use are appended to each battery. Cl. 2273, 2274, 2275. 1.10.0 No. 61 007. Accumulators. 857 60 998 — 61 003. 61 007. 1 : 5. 60.996. Battery of Accumulators (Feussner's), comprising 20 Cells. The Batteries can be combined in any number to form High Voltage Batteries as shown e. g. in Fig. 60,996 A The capacity is about 0.8 ampere-hours, the charging current being 0.1 ampere. The cells are firmly set in with paraffin and soldered together. Terminals are fitted on the end poles of the battery. 60.997. - - idem, comprising 25 cells Cupboards for High Voltage Batteries quoted for on application. Pig. 60,996 A, for example, shows a Battery of 500 Feussner Cells. £ s. d. 2. 5.0 2. 15. 0 Edison Accumulators, mechanically. Figure, in nickelled sheet steel boxes, imperishable electrically and List No. Capacity Ampere hours Mean discharge voltage on abt. 4-hour discharge Normal o Charge Amp. Current n Dis- charge Amp. Du- ration of char- ging hours Overall Dimen- sions of cell without pole- bolts length Width Height mm mm mm Weight unpa Without Caustic Potash kg per cell eked With Caustic Potash kg 21»/o Caustic Potash required per Cell kg Price per Cell with Caustic Potash £ s. d. 60998 8 1,23 3 2 33/4 24 85 145 0,45 0,55 0,1 0. 7.6. 60999 16 1,23 6 4 3*/4 45 86 160 0,8 1,1 0,3 0. 9.0. 61000 19 1,23 7,5 5 33/4 40 128 158 1,2 1,6 0,4 0. 12. 6. 61001 38 1,23 15 10 33/4 71 128 158 1,8 2.6 0,8 0. 17. 6. 61002 58 1,23 22 15 3'/4 103 128 158 2,7 3,8 1,1 1. 1.6. 61003 76 1,23 30 20 33/4 71 128 234 3 4,4 M 1. 7.6. When putting the cells in series the iron vessels must be insulated from each other. For this purpose the cells are built into wood carriers being insulated from each other in the latter by ebonite. Complete Batteries quoted for on application. £ s. d. 61.004. Syphon with Rubber Ball and Hydrometer for Edison Accumulators 0. 8. 6 61.005. Glass Tube for testing the correct level of the Electrolyte of Edison Accumulators 0. 0. 6 Accessories and Charging Devices for Accumulators. 61,006. 10 Litres Accumulator Acid of 1.21 specific gravity, in carboy 0. 6. 0 61,007. Specific Gravity Tester, Figure, hydrometer with rubber ball, glass case and rubber tubing, for determining the acid density j 0. 7. A glass vessel provided at the top and bottom with an open glass tube has a rubber ball fitted to the upper part and a piece of rubber tubing to the lower, while a hydrometer is contained inside. If the lower end of the tubing is introduced into the acid to be tested and the rubber ball squeezed the acid is drawn into the glass vessel owing to the diminution of pressure, and raises the hydro- meter in the vessel, the specific gravity of the acid being read from the hydrometer. Cl. 32 F, 68. 858 Voltaic Electricity. Section 1: Galvanic Sources of Current. No. <>1008- 61 008. 1 : 2. POLE INDICATOR illDICATEUR DE POLES POLSUUHER V r-SlZOVDlTS 61014. 1:1. II 1 II t -*• *- J -~ — HI 61 016 A. 61011. 1:2. 61 016. 1 : 8. 61.008. Pocket Voltmeter for 0 — 3 volts, Figure, electro-magnetic system with aperiodic adjustment A voltmeter — preferably of the pocket form — is visod for ascertaining the state of charge of the accumulator. The voltmeter has a spear which is firmly placed on one terminal of the cell, while a second spear attached to the short length of flexible is placed in contact with the other terminal. 61.009. - - i d e m, precision instrument after the Wesl on type, aperiodic and very accurate, 1.5 — 3 volts 61.010. Pole-finding Paper, colouring red at the negative pole. Price per book 61.011. Pole Finder, can be used up to 20 volts, in case, Figure 61. 012. -- idem, for 20—120 volts : . . . 61.013. -- idem, for 60 — 250 volts, built into mahogany box 61.01-4. Pole Finder, Figure, colouring red at negative pole, in case, with instructions — 220 volt Direct Current, charging current to 3 amperes at 110 volts and 1.5 ampere at 220 volts; with precision voltmeter for measuring the battery and net- work voltage, voltmeter switch, fuses and switch, Figure 5. 5. 0 til. 020. - - id e in, for charging currents to 6 amperes at 110 volts and 3 amperes at 220 volts 6. 0.0 (11.021. Giilcher's Thermopile, Figure, with 66 cells; excellently adapted for continuous work, especially for charging accumulators. Gas consumption, 170 litres per hour; useful terminal voltage, 2 volts; current 2 amperes 11.10.0 til. 022. Biernacki's Gas Tap, Figure (Fr. phys. Techn. I, Fig. 132), turning off auto- matically and opening an electric circuit when the flow of gas is small 1. 5.0 Cl. 5261,5071,5209, 2279, 3921. 860 Voltaic Electricity. Section 1: Galvanic Sources of Current. Nn. IH023 — New Thermopiles "Heil's Dynaphor", Figure, for working with gas. List No. Guaran- teed Effi- ciency Watts Groi of C Volts iping the ells Amps Pressure on open Circuit Volts Appro Diam. mm x. size Height mm Gas Con- sumption per Hour Litres Weight kg Price £ s. d. 61023 1,25 2,5 0,5 3,76 100 200 80 2,3 1. 9.0. 61024 2,5 5 0,5 6,3 200 250 140 3,8 2. 15. 0. 61025 3 3 1 6 210 380 140 3,7 4. 18. 0. 61026 3 1,5 2 3 210 380 140 3,7 4 18. 0. 61027 6 6 1 12 230 480 220 5,8 8. 0.0. 61028 6 3 2 6 230 480 220 5,8 8. 0.0. 61029 12 6 2 12 280 550 530 11,7 12. 8.0. 61030 12 3 4 6 280 550 530 11,7 12. 8.0. 61031 12 2 6 4 280 550 530 11,7 12. 8.0 61032 20 10 2 20 340 630 720 21 20. 15. 0. 61033 20 5 4 10 340 630 720 21 20. 15. 0. 61034 20 2,5 8 5 340 630 720 21 20. 15. 0. The guaranteed efficiencies are based upon a gas pressure of approx. 30 mm water. In places where the gas pressure is higher than 30 or 35 mm water it is necessary to insert pressure regulator No. 61,048 in the gas piping in order that the Dynaphor should not Ix-come damaged by overheating. These thermopiles are noiseless and odourless in their action. They are started up in a manner as simple as lighting an ordinary gas stove. -idem, for working with Spirit. Guaran- List No. teed Effi- ciency Grouping of the Cells Pressure on open Circuit Approx. size Diam. Height Spirit Con- sumption per Hour Weight Price Watts Volts Amps Volts mm mm Litres kg £ s. d. 61 035 3 I 3 1 6 210 380 0,16 3,5 5. 5.0. 61036 3 1,5 2 3 210 380 0,16 3,5 5. 5.0. 61037 6 6 1 12 230 450 0,25 5,8 8. 10. 0. 61 038 6 3 2 6 230 450 0,25 5,8 8. 10. 0. 61039 12 6 2 12 280 510 0,53 11 13. 0.0. 61040 12 3 4 6 280 510 0,53 11 13. 0.0. 61 041 12 2 6 4 280 510 0,53 11 13. 0.0. Burning spirit of 95% is necessary for working the spirit Dynaphors, this spirit being that generally obtainable. One charge of the basin is sufficient for about 10 hours working. Instructions for starting (this operation being very simple) are appended to each apparatus. — idem, for working with Paraffin Oil. Guaran- List teed Effi- Grouping of the Pressure on open Approx. size Paraffin Consump- Weight Price No. ciency Cells Circuit Diam. Height tion perHour Watts Volts [Amps Volts mm mm Litres kg £ s. d. 61042 12 6 2 12 280 590 0,25 13 14. 5.0. 61043 12 3 4 6 280 590 0,25 13 14. 5.0. 61044 12 2 6 4 280 590 0,25 13 14. 5.0. 61045 20 10 2 20 340 700 0,40 24 24 5.0. 61046 20 5 4 10 340 700 0,40 24 24. 5.0. 61 047 20 2,5 8 5 340 700 0,40 24 24. 5.0. Ordinary lamp oil is used for working above. One filling of the vessel is sufficient for about £ s. d. 10 hours continuous burning. Precise instructions for starting are appended to each apparatus. The paraffin flame, while making a slight amount of noise, burns quite blue and without odour. 61.048. Gas Pressure Regulator, suitable for all sizes of "Dynaphors" 1. 6.0 61.049. Relay for putting the Dynaphors in circuit when the necessary charging voltage is available (5 — 10 minutes after starting up), also for cutting out the cells when the heat supply is stopped 1. 3. o 61.050. Switchboard for accumulator with 1 supply-point for 20 amperes maximum, Figure 6. 10. 0 The switchboard, of polished oak, is fitted with 1 ammeter, 1 voltmeter. 1 current regulator with 21 contacts, and with 4 terminals for conducting and taking off the current. The price of the switch- board is increased by £ 1. 0. 0 if in marble. If desired the switchboard is fitted with a sliding rheostat in place of the current regulator. No. 61053. Thermopiles. 861 'W T* "— u I 61050 and 61052. 1 : 15. 61 027. 1 : 7. 61.051. Switchboard for accumulators with 2 supply-points for 20 amperes maximum, Figure The switchboard, of polished oak, contains 2 resistances, 1 precision voltmeter and 1 precision ammeter, 2 plug boxes, 1 voltmeter switch, 1 lamp bracket, 1 ammeter switch and 2 fuses. If with marble slab the extra price of switchboard is £ 1. 5. 0 It is very often desirable to have to branch off two circuits from a battery, the current strengths of which have to be regulated separately. The switchboard is excellently adapted for this purpose. 61.052. Cupboard for containing the Accumulators and a Thermopile, Figure, with the necessary connecting leads, but exclusive of thermopiles and accumulators According to the conditions existing relative to space, it will be necessary to settle the question of where to place the accumulators and the thermopile. Fig. 61,052 shows a cupboard fitted up with the thermopile and a 12-cell battery. The cup- board has a sheet iron grating at the upper part; the accumulators can therefore be charged with the cupboard completely closed without the latter becoming appreciably heated. The cupboard is provided with locks and keys in order to prevent any tampering with the contents. The length of the cup- board is 1.2 m, the height 0.8 m, and the depth 0.45 m, assuming that only 1 Gulcher thermopile is to be installed therein. If it is intended to contain 2 thermopiles the depth is then 0.6 m. 61,053. - - i d c m, for 2 thermopiles £ s. d. 12. 0.0 Experimental Switchboards for charging purposes and for use in connection with Accumulators: see Vol. I of this Price List, pp. 107 — 125; Resistances: see pp. 125 — 128, also following section on Apparatus for Current Conduction and Distribution. 4.10.0 5.10.0 Cl. 75, 33 r 862 Voltaic Electricity. Section 1: Galvanic Sources of Current. NIL (II O.'.l * * SffiHI •>• • ii * • 61 054. 61 056. Rectifiers for Charging Accumulators with Alternating or Three-phase Current. 61.054. Single Phase Alternating Current Rectifier, Koch system, for charging from 1 — 12 cells with 5 amperes maximum inclusive of charging resistance; without measuring instru- ments, as Fig. 61,054, but for fixing to the wall, also for connecting to one phase of a 3-phase system 61.055. - - idem, for charging 25 — 40 cells with 15 amperes maximum, with voltmeter and ammeter The following is the mode of action of this Rectifier: The armature of a polarised interrupter oscillates synchronously in the exciter circuit and in phase with the alternating current, by the appropriate employment of self-induction and capacity. Influenced by the voltage of the battery to be charged, this armature puts a contact into the main circuit in such manner that only current impulses in the same direction are admitted and the closing and opening take place exactly at the times of voltage equalisation between battery and alternating current. The contact thus works sparklessly and current losses are excluded. The apparatus can be used for all practical A. C. voltages to 240. When ordering, precise in- formation should be given as to number of cells, charging current, voltage and periodicity of the Alternating Current. 61.056. Mercury Vapour Rectifier, Figure, high efficiency, for charging Accumulators with single phase A. C., also for connecting up to one phase of a 3-phase system, for A. C. pressures from 105 — 120 or 200 — 240 volts and 50 cycles, for 6 — 14 cells; charging current 3 — 5 amperes, including a regulating resistance 61,056 a. - - i d e m, for 15—26 cells, 3—5 amps 61.057. - - idem, for 6 — 14 cells, charging current 4 — 10 amps., for connecting up to 105 — 120 volts A. C., 50 cycles 61.058. - - idem, for connecting up to 200 — 240 volts A. C., 50 cycles, 4 — 10 amps. . . 61.059. -- idem, for 15 — 26 cells, charging current 4 — 10 amps., for connecting up to 105—120 volts A. C., 50 cycles £ s. d. 12. 10.0 . 10.0 61.060. - - idem, for connecting up to 200 — 240 volts A. C., 50 cycles, 4 — 10 amps. . . 61.061. --idem, for 27 — 44 cells, charging current 4 — 10 amps., for connect ing up to 105 — 120 volts A. C., 50 cycles 13. 0.0 14. o. o 17.10.0 17. IT), it III. 0.0 18. 10. d 61,062. -- idem, for connecting up to 200 — 240 volts A. (\, 50 cycles. 1 — 10 ;nnps. . . Mercury Vapour Rectifiers for heavier Currents quoted for on application. The action of the mercury vapour reel il'i'T is based on the valvular action which lakes place al. the electrodes in a lilass vessel filled with mercury vapour. Its advantages consist in the hi<:!i efl'i ciency. the lack of actuated pails anil in the fact thai it is always ready for use. The number of cells, periodicity and voltage of the A. C. should be given when ordering. L'J. r>. 0 •jo. i:..o . Xo. filllliT. Alternating Current Rectifiers. 863 61 065 B. 61 065 A. 61 065 C. Single-Phase Alternating Current Electrolytic Rectifiers, Figs. A — C, for converting single phase alternating current up to 120 volts into Direct Current; also for connecting up to one phase of a 3-phase system: comprising 4 cells, 1 insulating stool, 1 starter and electrolytic salt sufficient for one charge. Fig. 61,065 A shows the complete rectifier, 61,065 B the arrangement of a cell, and 61,065 C the method of connecting up. List No. 61,063 61,064 61,065 61,066 61,067 Max. load Amps. 5 10 25 50 100 Constant load Amps. 1 2 5 10 20 £ 3.15.0 5.0.0 8.15.0 11.5.0 18.15.0 Each rectifier for A. C. consists of 4 cells each with an aluminium electrode in a solution of electrolyte salt, these cells allowing the current to flow in one direction only. By a suitable system of connections aU current rushes flow to the supply terminals in the same direction; a Direct Current is thus obtained. The method of connecting up for monophase A. C. is shown in Fig. 61,065 C for 120 volts. Each cell is suitable for rectifying 60 volts, so that the connections shown in Fig. 61,065 C are thus arranged for 120 volts, as only two cells are in series. By putting more cells in series a pro- portionately higher voltage is obtained and by connecting in parallel a higher current. A controller-starter is used for working the rectifier, this device consisting of a number of glow lamps, a short circuit switch and 2 connecting terminals for the A. C. lead. The A. C. switch should be closed when the short circuiting switch is open; the lamps then burn brightly until the cells have formed. As soon as the lamps become dim the forming is finished, the short circuit switch is closed and Direct Current can then be taken off. The D. C. thus obtained can be used forthwith for most purposes, e. g. for charging accumulators, exciting magnets, working X-ray apparatus with Wehnelt interrupters, etc. The use of a Condenser Cell, F i g. 61,084, is only necessary where a Direct Current of absolutely regular voltage is required. In conjunction with a cell of this kind the rectifier can be used with advantage for working a D. C. Arc Lamp in conjunction with an A. C. Network. The D. C. voltages are approximately as follows for the sizes for 25 amps, maximum load: Direct Current Supply Amperes Volts Alternating Current, 110 volts 50 cycles: D. C. Pressure 3-Phase Current, 120 volts, 50 cycles: D. C. Pressure . Volts 0 135 167 1 5 112 96 152 141.5 10 92 139 86 134 For charging acrumiil;ilors a proportionate number of resistances should be put in series when the number of cells is smaller (e. g. Nos. 61,015 — 61,018). £ s. d. C). 43111, 5874, 439'2. 864 Voltaic Electricity. Section 1: Galvanic Sources of Current. No. «1068 — 61 084. 1 : 6. Single-Phase Alternating Current Electrolytic Rectifiers, for Single-Phase A. C. to 240 volts; also for connecting up to one phase of a 3-phase system : comprising 8 cells, 2 insulating stools, 1 starter and electrolyte salt for one charge. List No. 61,068 61,069 61,070 61,071 61,072 Max. load Amps. 5 10 25 50 100 Constant load Amps. 1 2 5 10 20 £ 5. 15. 0 8. 5. 0 13. 15. 0 18. 15. 0 32. 10. 0 The 240 volt A. C. can, however, be transformed down to 120 volts by means of an A. C. trans- former and rectifier No. 61,063—61,067, D. C. of about 110 volts being obtained with a smaller load while the D. C. obtained with Nos. 61.068 — 61,072 has a pressure of approx. 220 volts. 61,073. Alternating Current Transformer 240/120 volts, secondary current 25 amps, maximum Three-Phase Electrolytic Rectifiers for converting Three Phase Current to 100 volts into Direct Current: compirisng 6 cells, 1 insulating stool, 2 starters and electrolyte salt for one charge. List No. 61,074 61,075 61,076 61,077 61,078 Max. load Amps. 5 10 25 50 100 Constant load Amps. 1 2 5 10 20 £ 6.15.0 8.5.0 13.15.0 18.15.0 31.5.0 The cells are the same as in the previously listed rectifiers for A. C., but they are a correspon- dingly larger number, and 2 starters instead of 1 are necessary. - idem, for Three-Phase Current to 220 volts: comprising 12 cells, insulating stool, 2 starters and electrolyte salt for one charge. List No. 61,079 61,080 61,081 61,082 61,083 5 10 25 50 100 1 2 5 10 20 9.10.0 13.5.0 22.10.0 30.0.0 50.0.0 As regards voltage, cf. remark in connection with Nos. 61,068 — 61,072. Max. load Amps. Constant load Amps. £ 61,084. Electrolytic Condenser, can be used for D. C. or A. C. to 120 volts, Figure, approx. 250 microfarads . 61.085. - - idem, approx. 500 microfarads . 61.086. Electrolyte Salt, )><»x containing 1.25 kg £ s. d. Spare Electrodes. For max. load Amps. ."> 1(1 I.Nt No. 61,087 61,088 Kadi £ 0. 1. 3 0. 1. 10 61,089 0.3.8 50 61,090 0.6.0 100 61,091 0. 12. 0 5. 0.0 1.10.0 1'. 10.0 0. !.'.<> C1]. 4396. No. 81 114. Voltaic Electricity. Section 2: Current Conduction and Distribution. 865 61 092 A. 1:10. I > Diagram of Connections. amp Rheostat Electrolytic Rectifier ; ^ J, Al. ] G 00 d Q f A. C.Wetwork J 1: Fe 61 092 B. G1D93. G1D9496. El 097. Bl 098. 61 099. 61100. 61101. 611027. 61114. 61108/13. 61,092. Demonstration Electrolytic Rectifier, Figs. A and B, for connecting up to single phase A. C. to 120 volts, for constant currents to 0.5 amp., max. load for short periods 2.5 amps., including salt for charging. Price without lamp resistance A Lamp Eesistance No. 61,015 is necessary for use in conjunction with above. Section 2: Current Conduction and Distribution. Leads and Wires: see Vol. I of this Price List, pp. 206 and 207, Nos. 51,154 to 51,162. 61,093. Terminal, Figure, for connecting two wires 0.0.10 0. 0. 7 0. 0. 7 re, 25 35 mm wide mm wide . 0.1. 3 0.0. 4 Terminals, Figure (W. D., Figs. 491 and 492 [466 and 467]), for connecting 2, 3 and 4 wires. List No. 61,094 61,095 61,096 For 234 wires £ 0.0.10 0.1.2 0.1.5 61.097. Terminal, Figure, simpler, for 4 wires 61.098. --idem, Figure, for strip and wires 61.099. --idem, Figure, for strip and wires 61.100. Carbon Terminal, for Bunsen Cells, F i g u 61.101. --idem, Figure, for Leclanche" Cells, 25 mm wide Terminals, Figure s, for screwing in a board, with lock nut, finely lacquered, in three sizes. Length 25 30 35 mm List No. 61,102 61,103 61,104 With 1 Screw £ 0. 0. 5 0. 0. 6 0. 0. 7 List No. 61,105 61,106 61,107 With 2 Screws £ 0. 0. 6 0. 0. 7 0. 0. 8 Terminals, F i g u r e, as preceding, screwed in a brass block which can be screwed on to a board by two wood screws. 25 30 35 mm 61,108 61,109 61,110 0. 0. 6 0. 0. 7 0. 0. 8 61,111 61,112 61.113 0. 0. 7 0. 0. 8 0. 0. 10 Length List No. With 1 Screw £ List No. With 2 Screws £ 61,114. Table Terminal, Figure, for screwing on: a) with 2 milled screws b) with 1 milled and 1 grub screw Cl 5354, 5174, 2-242/S2. £ s. d. 2.8. 0 £ s. d. 0.0. 4 0.1. 0 0. 1. 0 55 866 Voltaic Electricity. Section 2: Current Conduction and Distribution. No. 61 115 — 60 172 B. 1:6. 60 172 C. 61115. 61116. 61117. 1:3. 1:1. 1:1. 61118. 1: 1. 61119. 1:10. 61 120. 1 : 5. 61 121. 1 : 5. 60,172. Foot or Stand Terminal (Holtz's), Figure on p. 799, with grooved ebonite in- sulation (Ztschr. f. d. phys. u. chem. U. 2, p. 55) £ s. d. 0. 6. 0 The terminals hav heavy lead feet and are very useful for the greatest variety of experiments. Figs. 61,072 B and C s!.o v some adaptations. 61.115. Clip for Branches, Figure (M. T., Fig. 200) , 0. 4. 0 61.116. Pressure Terminal as suggested by Kolbe, nickelled, Figure, with 1 screw head. for sen wing in wood, ebonite or the like ,0. 0. 10 61.117. Double Pressure Terminal (Kolbe's), nickelled, Figure (Kolbe-Skellon, Introduction to Elec'.ricity, Part II, Fig. 117 K) 0. 1. 0 61.118. Triple Pressure Terminal (Kolbe's), nickelled, Figure, with screw nut for fixim: 0. 61.119. Ebonite Rod, 60 cm long, with 2 brass terminals having crossed holes, Figure (W. D., Fig. 504 [477]) 0. 12. 0 61,120. Single-pole Interrupter for Battery Currents, Figure (W. D., Fig. 489 [464]), on slate base, can also be used as a single-pole commutator 0.12. 0 0.18. 0 61,121. Single-pole Interrupter (Du Bois-Beymond's), Figure, on slate base and with screw clamp, very convenient to manipulate (M. P., 10lh edn., IV, 1, Fig. 329; 9th edn., HI, Fig. 334) Quick-Break Lever Switches, Figure, for Heavy Currents, on slate, for voltages up to 550. Amperes 35 60 100 200 Single-pole, List No. 61,122 61,123 61,124 61,125 £ 0.3.6 0.5.0 0.6.6 0.9.6 Double-pole, List No. 61,126 61,127 61,128 61,129 £ 0. 6. 6 0. 9. 6 0. 12. 6 0. 19. 0 Triple-pole, List No. 61,130 61,131 61,132 61,133 £ 0. 10. 0 0. 14. 0 0. 19. 0 1. 8. 0 61.134. Commutator, KuhmkorlTs. Figure (M. P., 10th edn., IV. 1. Fig. 33S; <>"' edn., III. Fig. 335) 0.16. 61.135. Commutator, Knhmkort'fs, with Kolbe automatic current-direction indicator, Figure (Kolbe-Skellon, Introduction to Kleet ricity. Part II. Fig. !>".) 1. 5. 0 01. -'-'•'.:'. 5T48, li:n 4175,5833, 'J'J .... Xo (!1 142. Terminals. Switches. Reversing Switches. 867 61 126. 1 : G 61 134. 1 : 4. 61 135. 1 : 4. 61 136. 1 : 0. 61 137. 1 : 4. 61 139. 1 : 5. 61 138. 1 : 3. 61 140. I : 6. 61 141. 1 : 6. 61 142. 1 : 4. 61.136. Commutator (Hermann's), Figure (W. D., Fig. 490 [465]), very neat type . 61.137. Commutator (Berlin's), Figure, easily understandable and very neat (Gan.-Man., Fig. 741) ! 61.138. Mercury Switch (Pohl's), Figure, can be used both as a commutator and a reversing switch (M. P., 10th edn., IV, 1, Fig. 339 b; 9th edn., Ill, Fig. 337) .... 61.139. Plug Commutator, Figure, on ebonite slab and with screw clamp 61.140. Commutator (Haiti's), for Heavy Currents The apparatus is mounted on a stand on round slate base; the connections made can be easily follow- ed by the audience. 61,111. Press Contact on wood board, with terminals, Figure (M. P., 10lhedn.,IV, l,Fig. 334) j 0. 5. 0 61,142. Key with Mercury Contact (Kolbc's), Figure (Kolbe-Skellon, Introduction to Klcctricity, Part II, Fig. 102) £ s. d. 1. 0. 0 1. 4. 0 1. 4. 0 1. 2. 0 3. 0. 0 Cl. 5807, 5830, 5816, 5829, 2258, 2259, 2261, 5809, 4549. 0. 6. 0 2260, 55* 868 Voltaic Electricity. Section 2: Current Conduction and Distribution. Nu. 61 143 — 61143. 1:3. 61 144. 1 : 3. 61 146. 1 : 6. 61 153 B. 1:5. 61 156. 1 : 5. 61.143. Key, Figure, for temporary or permanent closing of a circuit The key is mounted on ebonite and can be fixed to the table by two screws. 61.144. Double Key (Successive Key), for the Wheatstone Bridge, Figure One circuit is closed first by pressing the knob, stronger pressure closing a second. « 61.145. -- idem, with galvanometer Back Key, specially for moving-coil galvanometers 61.146. Discharge Key (Heim's), Figure, for capacity determination (E. T. Z. 11, 1890, p. 556) 61,147. Morse Key, Figure, with platinum contact, for weak currents Multiple Commutators, Figure (W. D., Fig. 486 [461]), arranged so that the cells or accumulators to be connected up can be put in scries, in groups or in parallel, with wood cylinder. List No. 61,148 61,149 61,150 61,151 For 4 (I 8 1- cells Voltage available on connecting up) 0 A single accumulators . . . volts) -' 4' * £ 2.0.0 2.8.0 3.4.0 •> t i\ * i-> •> i 5.8.0 Multiple Commutators with Stabilit Cylinder and Slate Insulation, for currents to 10 amperes. Figs. A and B. No. 61,152 61,153 61,154 61,155 For 6 1L> cells Voltage available on connect ing ,,,,| 12 single accumulators .... volts j £ 4. 16. 0 6.0.0 7.4.0 £ s. d. 0. 10. 0 1. 5.0 1. 10.0 L'. 10.0 0. 1(1.0 9.0.0 Cl. 4676. 4540. U '. .-,s(ii;, L'-.'tn, -.".'41. No. 61237. Keys. Sliding Resistances. 869 61 174. 1 : 3. 61 206. 1 : 3. £ s. d. 61.156. Multiple Commutator for Heavy Currents, Figure, for 4 groups of 20 amperes each 7. 0. 0 The commutator is used for connecting up 4 groups of primary or secondary cells in three different ways according to requirements: (1) all 4 in series (20 amps, with quadruple the voltage of a group); (2) 2 groups in parallel (40 amps, with double the voltage of one group); (3) all 4 groups in parallel (80 amps, with the voltage of one group). 61.157. -- idem, larger, for 4x80 amperes 11.0.0 Sliding Resistances, Figure, for table use and for firmly fixing, of constantan wire wound on an insulating weldless steel tube. Model A Model B Model C Model D Model E Model F Max. Appr. weitrht 0.4 ktr Appr. weight 0.6 kg Appr weight 0.9 kg Appr. weight 1.5kg Appr. weight 1.8 kg Appr. weight 2.2 kg load D iam. 30 mm Diam. 35 mm [Ham. 40 mm Diam. 50 mm Diam. 55 mm Diam. 60 mm Length 128 mm Length 168 mm Length 208 mm ' Length 3U8 mm Length 408 mm Length 458 mm 1 ;«r j • . T.i«t T . . T i«f T Jut Amp Otiras Ijlnl No. s. No. s. d. nhin* ij»i Ohms V() s. d. Ohns ijlnt No. s. d. Ohms IjlhL No. s. d. 0,3 400 61158 11.0 74061166 13.0 lir.u 61174 15.6 207061182 19.0 3375 61190 21.0 4130I61198 25.6 1,0 so 61159 11.0 15061167 13.0 235 61175 15.6 42561183 19.0 680 61191 21. 0 865 61199 25.6 2,0 L'S 61160 11.0 62 61168 13. 0 85 61176 15.6 158 61184 20.0 250 61192 22.0 315 61200 26.6 3,0 17 61161 11.0 32 61169 13. 0 48 61177 15.6 87 61185 20.0 140 61193 22.0 172 61201 26.6 4,0 7 61162 11.0 14 61170; 13.0 21 61178 15.6 4761186 20.0 6061194 22.0 75 61202 26.6 5,0 2,6 61163 12.0 5 61171s 13. 6 7,5 61179 16.6 1361187 21.0 19 61195 23. 0 26,5 61203 27.6 10,0 0,9 61164 12.0 1,6 61172 13. 6 2,6 61180 16.6 4,761188 22.0 7,3 61196 23.0 9,2 61204 27.6 20,0 0,4 61165 12.0 0,8 61173 14. 6 1,3 61181 17. 6 2,361189 23.0 3,6 61197 25. 6 4,6 61205 30.0 If specially ordered, all the above listed Eesistances can be supplied without sliding bar and sliding brush, but with feet for using as fixed series resistances. In this case the prices are decreased by in Model A Model B Model C Model D Model E Model F About £ 0. 3. 0 0. 3. 6 0. 4. 0 0. 4. 6 0. 5. 0 0. 6. 0 Double Sliding Resistances, Figure, consisting of 2 sliding resistances as above, which can be put in series or parallel. KM. i Series Load i Parallel Resistance in Series' Parallel Model G Appr. Wt. 1.2kg Length 208 mm Resistance in Series Parallel Model H Appr. Wt. 3.6 kg Length 308 mm Resi i Series stance n Parallel Model J Appr. Wt. 3.0 kg Length 408 mm Resi i Series itance n Parallel Model K Appr. Wt. 3.5kg Length 458 mm Amperes Ohms List No. s. d. Ohms List No. s. d. Ohms List No. s. d. Ohms No. s. d. 0,3 1,0 2,0 3,0 4,0 5,0 10,0 20,0 0,6 2,0 4,0 6,0 8,0 10,0 20,0 40,0 2300 570 170 96 42 15 5,2 2,6 575 142 43 24 10 A 4 1,3 0,6 61206 61207 61208 61209 61210 61211 61212 61213 26.6 26.6 26 6 26.6 26.6 27.6 27.6 30.0 4140 850 316 174 94 26 9,4 4,6 1030 212 80 43 23 6,5 2,4 1>2 61214 61215 61216 61217 61218 61219 61220 61221 33 0 33.0 33.0 33.0 33.0 35.6 35.6 40.0 6750 1360 500 280 120 38 14.5 7,2 1610 340 125 70 30 9,5 3,8 1,8 61222 38.6 61223 38.6 61224 38.6 61225 38.6 61226 38.6 61227 41.0 61228 41.0 61229 44.0 8260 1730 630 340 150 52 18,5 9,0 2060 435 158 85 38 13 4,6 2,2 61230 61231 61232 61233 61234 61235 61236 61237 46.6 46.6 46.6 46.6 46.6 48.6 50.0 55.0 Ohm Scale tor reading the resistance inserted, per scale Model G H J K £ 0.2.6 0.3.0 0.3.0 0.3.6 Cl. 5848, 5847. 870 Voltaic Electricity. Section 2: Current Conduction and Distribution. N.I. (il -.MS — 61 246. 5. Universal Sliding Resistances, Figure, comprising a combination of 2 sliding resistances whose resistances are of different magnitude and varying loading capacity, it being possible to use these as required in series, parallel, or singly by means of a connecting strap. An extermdy complete range of tine adjustment of the current-value to be regulated is possible with these resistances and in consequence they can be highly recommended both for this reason and by- virtue of their many sided uses for practical and scientific purposes. Max. Load Model L Approx. weigth 1.4 kg Length 208 mm Model M Approx. weigth 3.0 kg Length 308 mm Model N Approx. weigth 3.5 kg Length 408 mm Model 0 Approx. weigth 4.5 kg Length 4.~>s MUM Amps. Ohm* ^ s. d. Ohms kwt g d Ohms List No , a. Ohms List No. s' (l 0,3 1,5 1150 112 61238 36.0 22 ^ , 61 242 41. 0 3375 330 61 246 47. 0 44™ 61 250 53. 0 1,0 4,0 235 21 61239 36.0 425 47 61 243 41. 0 680 60 61247 47.0 865 75 61251 53.0 2,0 7,0 85 4,5 61240 37.0 158 8,2 61 244 42. 0 250 13,2 61248 48.0 315 16,5 61252 54.0 5,0 20,0 J':! 61241 38.0 J.,0 13 2,3 61 245 43. 0 19 3,6 61 249 49. 0 26.5 4,6 61253 55.0 (il.L'.Vl. Stepped Sliding Resistance, Fig. 61,174. p. 869, wound with wire of different thick- nesses, for taking current from cells and accumulators. The range of regulation is extremely wide With minimum Connected to external resistance .of Capable of Regulation from •2 Volts 0.1 Ohm 5 Ai'lli-Amps. to 20 Amps. 4 „ 0.2 „ 10 „ „ 'JO .. 6 „ 0.3 „ 15 „ .. 1!0 „ 10 „ 0.5 „ 4Q ,, ., -0 ,, £ s. .1. •2. 0. (» (>!,'.;.->.">. Stepped Double Sliding Resistance, has the above-mentioned loading capacity and double Hi'- resistance when in series; when in parallel the resistance ts halt' as much with double the loading capacity I. 0. o The Constant Load with maximum current applies when the Sliding Resistances are arranged vertically. Nickelin Wire for Series Kesistances, bare. I Ham. mm 0.5 0.7:. 1 1.1 1.3 1.5 2 1'.:. 3 Approx. resis- tant' per m, Ohms L> 0.9 (1.5 (LI'-' 0.3 O.L'L' (l.r_> O.OS1 0.0.-) 7 List V->. 61,256 61,257 61,258 61,259 61,260 61,231 61,262 61,263 61,264 Pri< •(• per kg t 0. 7. 0 0. 7. 0 0. 7. 0 0. 7. 0 0. 7. 0 0. 7. 0 0. 6. 6 0. 6. 6 0. 6. 6 (il.'J(J5. Nickelin Wire of various thicknesses, bare, altogether 5mi grams 0. 4. CI. 5HU2 MAX KOHL A. G., CHEMNITZ, GERMANY. Notice No. 18. Experimental Resistances with Z Weft Contacts, as suggested by Dr. W. Briisch, Liibeck, constructed by Max Kohl, Ltd., Chemnitz. We have, at the instigation of Dr. W. Briisch of Liibeck, con- structed the Experimental Resistances with 2 Switch Contacts, described below. This type of resistance admits of a variety of adaptations, being particularly suitable for taking from heavy current supplies any large or small currents at low terminal voltage. Type A, Fig. 1, with 39 contacts — Resistance, 36 ohms - maximum permissible load, 5 to 30 Amps, according to the position of the contact handles — for taking currents of from 0.03 to 30 Amps, and pressures of 0.3 to 110 Volts from the network. Type B, Fig. 1, with 39 contacts - - 48 ohms resistance - max. permissible load 5 to 20 Amps, according to the position of the switch handle - - for taking currents of 0.08 to 20 Amps, and pressures of 0.8 to 220 Volts from the network. Type C, Fig. 2, — with 21 contacts — 24 ohms resistance - max. permissible load 5 to 20 Amps, according to the position of the switch handles -- for taking currents of from 0.08 to 20 Amps. and pressures of 0.8 to 110 Volts from the network. The terminal designated "O" is connected up to the zero end of the resistance, while that designated ///. is connected with Type A and B. Fig.T. 1 : 8. the other end of the same; terminal /. is connected up to Switch Contact /. and terminal //. to Switch Contact //. The resistances can be used in three different manners. Grouping No. I. As a Series Resistance, Fig. 3. This method of using the resistances can be recommended in the case of apparatus where there is no interruption of the current, for taking heavy currents where the terminal voltage at the apparatus is fairly high (e, g., for working an arc lamp). Coarse regulation is obtained by Switch Contact No. /., while finer steps can be had by em- ploying No. //. In this connec- tion, the fol- lowing current- strengths should not be exceeded in the case of each type: - I. Grouping as a Series Resistance. To the Apparatus Type C. Fig. 2. 1 : S. Fig. 3. Type A. Type B. Type C. Large Pattern with 39 contacts; Resistance Large Pattern with 39 contacts: Resistance Small Pattern with 2 contacts; Resistance 36 Ohms, for connecting up to 110 Volts. 48 Ohms, for connecting up to 220 Volts. 24 Ohms, for connecting up to 110 Volts. Resistance Permissible Current Resistance Permissible Current Resistance Permissible Current Ohms Amps. Ohms Amps. Ohms Amps. 0 to 0,4 30 0 to 1 20 0 to 0,4 20 0,65 „ 1 25 1,4 „ 5 15 0,7 „ 1 15 1,25 „ 2 20 6 „ 14 10 1,5 „ 3 12,5 2,4 „ 6 15 16 „ 36 6,5 4 „ 6 8,5 7 ,,12 10 40 „ 48 5 8 „ 24 5 14 „ 24 6,5 27 „ 36 5 M. 18e. (2. A.) Copyright strictly reserved. Cl. 3769, S770, 4719. Max Kohl A. G., Chemnitz, Germany. Net- work Ammeter II. Grouping as a Shunt Resistance. To the Apparatus Grouping No. II. As a Shunt Resistance, Fig. 4, for taking off any Currents (within the limits of load) at low Pressure. It is advisable first of all to place Switch Contact /. on the highest resistance- value and Contact //, on "O", the latter being moved forward until the desired current-density is reached. If Switch Contact //. is still near to "O" and should a further slight increase in the current still be necessary, it is better to move Switch Handle /. back than No. //. forward. In feeding apparatus which work with an interrupted current (e. g. induction coils with platinum interrupters) too high a tension should not predominate when the current is admitted otherwise there is danger of the contacts getting burned. When heavy currents are being used, Switch Contact No. //. should be left near to O and Contact /. moved back cautiously. The pressure at the apparatus when the current is being admitted is to the working voltage as the resistance-values given alongside the contact studs on which the Handles are placed are to each other. The maximum permissible currents given under (1) should in no case be exceeded. Grouping No. III. As a Shunt Re- sistance, Fig. 5, for taking off small Currents .!?",". 4 (C ^ Ammeter up to 2 Amps. As a rule both Switch Contact Handles are first of all placed on the zero contacts, the III Grouping as Shunt Resistance for small currents. To the Apparatus current in the apparatus being slowly increas- ed by adjusting one of the Contact Handles. If Handle No. //. is placed on the spot where No. /. previously stood, and vice-versa, this changes the poles at the apparatus. Under no circumstances whatever must this method of grouping be used for taking off higher current- densities than 2 Amps. A too heavy current - - with con- Fig. s. sequent burning out of the resistances - - is particularly liable to take place when one Handle is near the highest resistance-value and the other close to the zero-value and the resistance of the apparatus itself is small. The latter would cause most of the spirals to short-circuit and the thin spirals, in series, near to the maximum resistance-value would then be charged with a current exceeding that prescribed. It is always advisable (as also in the case of other methods of employing the resistances) to connect up a reliable ammeter for protecting the resistance and the apparatus connected up. The total current flowing through the resistance, when connected up in accordance with Scheme No. ///. should not exceed 5 Amps. PRICES. 50516. Experimental Resistance, Type A, Fig. 1, with 2 Switch Handles, 39 Contacts; Resistance 36 Ohms; maximum permissible load, 5 to 30 Amps., according to position of Contact Handles; for taking currents of 0.03 to 30 Amps, and pressures of 0.3 to 110 Volts from the supply line .£'6.15.0. 50517. Experimental Resistance, Type B, Fig. 1, with 2 Switch Handles, 39 Contacts; Resistance 48 Ohms; maximum permissible load 5 to 20 Amps., according to the position of the Switch Handles; for taking currents of 0.08 to 20 Amps, and pressures of 0.8 to 220 Volts from the supply line ,,6.15.0. 50518. Experimental Resistance, Type C, Fig. 2, with 2 Switch Handles, 39 Contacts; Resistance 24 Ohms; maximum permissible load, 5 to 20 Amps, according to the position of the Switch Handles; for taking currents of 0.08 to 20 Amps, and pressures of 0.8 to 110 Volts from the supply line ,4.1.0.0. Max Kohl A. G., Chemnitz (Germany). Supplement to Notice No. 18. Simple Experimental Switchboards. In addition to being makers of the most complete patterns of experimental switchboards, we ul so manufacture those of a lighter and simpler pattern, which, however, permit of being used in a multiplicity of ways. On the one hand they permit of connecting up the apparatus which are being used for teaching purposes (and which are usually intended for working on low pressure) to the heavy current from electricity works; while on the other hand they permit of carrying out those experiments which imply the use of a heavy current, e. g., demonstrating the electric arc. The switchboards are accordingly arranged in such manner that it is possible to work with small or large current-densities at high or low pressures when the supply is obtained from a heavy current system. The condition as regards low voltage, which is rendered possible by a shunt method of connecting (division of pressure), is particulary important in the case of apparatus working with interruption of the current, the contact parts of which are burnt out when a high voltage is applied or even when a large series resistance is employed, since the full supply voltage prevails at the contact parts at the moment of interruption of the current. The switchboards are fitted either with Deprez-d'Arsonval precision measuring instruments or with air-damped electromagnetic instruments, as desired. The former are rather advisable, as they have a uniform scale and are dead-beat. They are only applicable for direct current. The electromagnetic instruments possess a scale which commences only at approx. 1/5 of the maximum deflection. Smaller currents and voltages can thus only be read approximately. On the other hand, however, these instruments can b&--used both on direct Fig- 6. l : 10. and alternating current. Alternating current, however, is only directly applicable for a few experiments, so that it is usually necessary to trans- form it into direct current. The construction of the switchboards may be seen on reference to Figs. 6 and 7. A marble slab is placed on one of the Double Switch Contact Resistances already described, this slab containing the necessary fuses, switches and measuring instruments. The method of connecting is generally in accordance with that described on pp. Ill and 112 of our Price List No. 50, with the exception that the measuring instruments cannot be commutated, and that they give the voltage and current in the apparatus direct. The switchboards are designed for fixing on the wall. Directions for use and a diagram of connections are appended to each switchboard, l : 9. The metering instruments have an approx. base diameter of 130 mm. Prices. 7086. Simple Experimental Switchboard, Type EA\, for connecting up to 110 volts D. C., Fig. 6, with Double Switch Contact Eesistance, 39 contacts, 36 ohms; max. permissible load 5 to 30 amps, according to position of Switch Contacts; for taking currents of 0.03 to 30 amps, and pressures of 0.3 to 110 volts from the supply ; with Precision Instruments £ 13. o. 0 The marble slab contains: 2 terminals for the supply current ; 2 fuses; 1 main switch; 1 switch lor the shunt; 1 Precision Ammeter; 1 Precision Voltmeter; 2 terminals for connecting up the apparatus. 7087. -- idem, Type EB\, Fig. 6, style as No. 7086, but for connecting up to 220 volts D. C., with 2 Switch Contacts, 39 contacts, 48 ohms; max. permissible load, 5 to 20 amps, according to position of switch contacts; for taking currents of 0.08 to 20 amps, and pressures of 0.8 to 220 volts from the supply £ 13. 5. 0 M. 18 A e. Cl. 6231, 6234. Max Kohl A. G., Chemnitz (Germany i. 7088. - - idem, Type EC\ , Fig. 7, Fittings as No. 7086, for connecting up to 110 volts D. C., with Double Switch Contact Eesistance, 21 contacts, 24 ohms: max. permissible load, 5 to 20 amps, according to position of switch contacts; for taking currents of 0.08 to 20 amps, and pressures of 0.8 to 110 volts from the supply £ 10. :>. it 7089. Simple Experimental Switchboard, Type EA.lt Fig. 6; fittings and load-limits as No. 7086, but with electromagnetic Measuring Instruments, can be used for D. C. and A. C. £ 11. \~>. :i7l. .iS.f 1 , ,'i.s j'2 . No. (il ::<>:!. Moving Magnet Galvanometers. 877 61302, 50119 and 61310. 1 : 10. 61 303. 1 : 6. If the two coils are connected in opposition a differential galvanometer results. If the second magnet is moved into the upper half of the suspension an astatic galvanometer j is obtained. The galvanometer has a scale divided every 10° for the scholars, a second scale, divided in single degrees, being provided for the teacher. As the pointer is arranged to rotate relatively to the magnet, its point can always be directed towards the scholars after the winding plane of the coils have been placed in the magnetic meridian. Sensitivity with one magnet -- e. g., without astaticity - - with coils in series: 1 deflection = approx. 0.00004 ampere. Each coil has a resistance of about 3.5 ohms. The sensitivity is ample for all ordinary school experiments. 61.300. Tangent Galvanometer Ring for above, of copper, on wood tripod, the baseplate of the galvanometer fitting and rotating about the round top of this tripod, cf. Fig. 61,300 A Set up as a tangent galvanometer the instrument is suitable for measuring currents to 15 amperes (10 amps. = approx. 60° deflection). For accurate reading the large pointer is changed for another intended for reading the fine scale. 61.301. Accessories for carrying out magnetometrical measurements in conjunction with No. 61,299, cf. Fig. 60,127, comprising: Aluminium Case with marks for taking 20 gram brass weights for determining the moment of inertia; Graduated Slider; Bar Magnet; Table for the Galvanometer and Graduated Bar with Measuring Wire, which can be used at the same time as a Wheatstone Bridge 61.302. Reflecting Galvanometer, Weinhold pattern, Figure (W. D., Figs. 508, 509 [481, 482]), cf. also Fig. 61,303, for setting up permanently on wall bracket or suspended board, with one coil having two different windings. Price exclusive of suspended board and lamp , The galvanometer has a Topler adjustable air damping arrangement, astatic needle with pointer reading, mirror for reading by lamp and scale, transmission chamber with lens and one coil, the latter being provided with one group of windings of thick wire (approx. resistance 0.5 ohm) and one group of fine wire (approx. resistance 500 ohms). The ends of both windings are carried to three terminals, the latter being connected by three wires and three terminals alongside the lecture table. If required the thick or fine winding can be used in this manner and without altering anything on the galvano- meter. The precise resistance of the two windings is given on the coil. The following sensitivities are obtained with a medium period of swing (about 20 seconds for the complete period): 1 mm de- flection at a distance of 1 m == approx. 1.5 xlO 8 amp. or approx. 7 xlO-' amp. 61.303. --idem, Figure, with two coils, one with thick and one with fine winding; with change-over switch so as to enable the groups of windings to be put in series or punillel 1.10.0 3. 10.0 10.0 9. 0.0 Cl. 1'324, (104. 878 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. No. 61 304 — 61 304. 1 : 5. 61 308. 1 : 4. 61.304. Reflecting Galvanometer, F i g u r e, arranged as ^"o. 61,302, but with copper damper and hell-shaped magnet; it is therefore less sensitive than No. 61,302. With transmission chamber and one pair cylinders with two different windings 61.305. - - i d e m, with two pairs cylinders, one with thick and one with fine winding . . 61.306. Reflecting Galvanometer, Figure, smaller, with detachable oil damper, pointer and mirror reading, transmission chamber and lens, with one coil having two different windings 61.307. Reflecting Galvanometer with two coils, one having thick and the other fine winding, otherwise exactly as No. 61,306 61.308. Model of a Reflecting Galvanometer, Figure, as suggested by Weinhold, with air damping (\V. I')., Figs. 543 a— c [516 a — c]) Moving Coil Reflecting Galvanometers: see further on in List. Reflecting Galvanometers Nos. 61,302 — 61,307 can also be employed with Telescope Reading. It is advisable, however, to insert a polished plane mirror so as to obtain a clear image. 61.309. Extra Price for a polished plane mirror Accessories for Reflecting Galvanometers. 61.310. Paraffin Lamp with slotted chimney, for Reflecting Galvanometers, F i g u r e, on stand til. 311. Incandescent Gas Burner for Reflecting Galvanometers, on stand and with slotted chimney, Figure 60,71H. Electric Incandescent Lamp on stand with protecting chimney, Fig. »;u.71.s, p. 842, for Reflecting Galvanometers The glow lamp is of the long filament type. Vulture to he staled ulien ordering. If this is not <|iioteil ue supply 1 1<> volt lamps. !.">. Spare Glow Lamp for pressures to lio volts 61.311. -- idem, for 150 or 220 volts I!l.:;i5. Nernst Lamp on stand and with protecting cylinder; I'm1 use only mi Direct Cm-rent at 110 — 220 volts; giving a very bright image £ s. d. 7. 10.0 ! 8.15.0 4. 0.0 5. 0. 0 1. 8.0 0. 8.0 0. 8.0 0.12.0 0. 18. 0 o. 3.0 0. 4.0 1. 4.0 Cl. 2326, 2328. 2358 No. 61321. Reflecting Galvanometers. 879 61 310. 1 : 6. 61 311. 1 : 6. 61 316. 1 : 8. 61 320 A. 1:3. 61 320 B. 1:3. 01.310. Nernst Lamp, Figure, with Condenser and Projection Lens, for projecting the \ & «• d. diaphragm placed in front of the condenser on to the scale; for 110 — 220 volts Direct i Current only, with wall bracket j 5. 0. 0 50. 121. Terminal Board with 3 terminals on serpentine base, for fixing on the wall, also 7 metres triple flexible cord and 6 porcelain cylinders, for Galvanometers Nos. 01,302, 01,304, 61,300 ' . 0.12.0 61,317. Terminal Board with 2 terminals and triple flex, as No. 50,121, for Galvanometers Nos. 61,303, 61,305, 61,307 j 0. 10. 0 01.320. Shunt for Reflecting Galvanometers, Figures A and B (W. D., Figs. 510 and 511 [483 and 484]), consisting of a resistance box with resistances of 3/7"', Vg"'? 3/97lhs> 1/99tll> 3/997ths» V999"1) 3/9997> ' /99991" value of the galvanometer resistance, for enabling 0.3, 0.1, 0.03, 0.01, 0.003, 0.001, 0.0003, 0.0001 of the current to be. measured to be passed through the galvanometer 2. 14. 0 When ordering the resistance of the galvanometer coil for which the arrangement is intended should bo given or the coil sent to us. In galvanometers having two coils the shunt is usually wound for the high resistance coil. 61.321. -- idem, smaller, for shunting 0.1, 0.01, 0.001 and 0.0001 of the current to be measured 2. 6.0 50,118. Bracket for Reflecting Galvanometers, Figure 50,118, p. 21. Price without Gal- vanometer and Scale 0. 8. 0 It is preferable to set up the instrument on a bracket fixod to the wall if space permits rather than on a suspended board fixed to the ceiling as the vibrations of the ceiling have a disturbing action in many cases. 50,119. Suspended Board for Reflecting Galvanometers, Figure 50,119, p. 22, with nickelled brass rods and polished board. Price, excluding Galvanometer 50,112. Galvanometer Scale, 4 m long, painted on linen, divided in decimetres, the metres figured, for fixing to the wall 1. 10.0 0. ]2.0 50, 123. - idem, 6 m long ! 0. 16. 0 CI. IS'-', 2330, 2332, 2333, 2334. 880 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. No. 81 322 — 61 329. l : r>. 61 327. 1 = 5. 50,124. Transparent Galvanometer Scale, 2 m long, of ground glass, in wood frame, divided every ."> centimetres, with lugs for suspending on the ceiling, Figure on p. 21. . Tiiis scale is suspended at a distance of about 2 rn from the galvanometer. U'itli its aid it is possible to iiiTiiiifff the ^alvanoinctcr and scale in front of the audience. 61.322. School Galvanometer (Nobili Multiplier), Figure, with astatic needle and detachable oil damping, with one coil having thick winding; to he used mainly for thermal currents. with pointer reading (cf. (Jan.- Rein.. Fig. 830) 61.323. -- idem, with one coil having two windings of different resistance, for thermal and induction currents 61,324. -- idem, with two interchangeable coils (if different resistance, for thermal and induction currents . £ s. d. 0. 17.0 3. O.Oj 3. 10.0 4. 0. 0 ci. 23:c.' 2348, 2:ill. Nn. lil Ml. Moving-Magnet Mirror Galvanometers. 881 E 61 331 B. 1:3. 61 331 A. 1:4. Luminous Pointer for Galvanometry and Magnetometry after Friedr. C. G. Miiller: see under No. 60,132, p. 795. 61.325. Lecture Galvanometer after v. Beetz, Figure, with pointer reading, with one Coil with thick wire 61.326. - - i d e in, with two Coils, one with thick and one with fine wire This galvanometer has been essentially improved by us especially as regards ease of changing the coils. It has a bell-shaped magnet and large copper damper, vertical scale visible at a distance, with Mack graduations and figures on white ground, and directing magnet. The whole instrument can turn about a tripod. 61.327. Lecture Galvanometer after v. Beet/, Figure, with pointer and mirror reading, with polished plane mirror, and with one Coil with thick wire 61.328. -- idem, with two Coils, one with thick and one with fine wire ....... 61.329. School Galvanometer after Noack, Figure (Ztschr. f. d. phys. u. chem. 1T. 5, p. 103) . . . •. The galvanometer has two adjustable coils, vortical tangent and degree graduations easily visible, bell-shaped magnet with copper damper, and can rotate on the base. It can be used both as a demon- stration and differential galvanometer, as also for measurements, and can even serve as a voltmeter. Total resistance, approx. 350 ohms. The scales are capable of rotation so as to be able to turn the zero point towards the audience. For thermo-electric currents the galvanometer is supplied if desired with coils of lower resistance. 61.330. -- idem, with mirror, so as to be used as a reflecting galvanometer 61.331. Large Mirror Galvanometer after Wiedemann, Figs. A and B, rotating on tripod, with graduated metal prism and adjustable coils, with bell-shaped magnet and spherical damper, and with ring magnet, with auxiliary weight and adjustable plate damper, with polished plane mirror for telescope reading or objective projection; also with improved magnet- and mirror-suspension; with one pair coils having 4x500 == 2000 turns, diffe- rentially wound; the mairncts and damper pertaining thereto are each placed in one case, F i g. 61,331 B . . . With annular magnet and auxiliary weight the galvanometer can be used as a ballistic instrument. d. 6. 0.0 7. 5.0 7. 10. 0 8. 15.0 8. 0.0 9. 10. 0 22. 10.0 Cl. 2365, 2366. 882 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. 61333. 1 : 7. 61 34.2 1 : G. 61842, 61848 end 61846. 1:8. 61.332. Large Mirror Galvanometer, as preeediiv:, but with bell-shaped magnet and spherical, (1 unper. Magnet and damper in case 61.333. - - idem, but with annular magnet, weight and adjustable plate damper. Magnet, and damper in ease Can l>e n>ed as hall's) ir j;;dv;monieter. 61.334. Extra price for Screw Motion for tin- Coils in Galvanometers Nos. (51,331 — 01.333 t i I, :t: :tr>. Pair of Coils for Wiedemann Galvanometer. Thickness of Wire Kuinlirr of Tunis For thermo-electric currents ... For Ordinary Galvanic \Vor!» . . n.~> nun For Physiological purpoi'-s. for I (| .,_() ^ mm Muscle and Nerve Currents . . I ' 4 x '.on L'lliin ( 4 x!500 = IK H in J 4 X3IHIII ll'IIIMI X5000 'JIM II II I xSOOO = 3-_'i MII i differentially wound dillevenlially £ 8. (1. 18. 0. 0 !'.». 0. 0 3. 0. 0 I 10. 0 2. 12. 0 1. in. (i •_'. I--', ii 2. is. ii .'!. III. II .->. III. II Cl. 'JSG^, 58..- No. 61 346. Moving-Magnet Mirror Galvanometers. 883 50 119, 61 345, 61 389. 1 : 9. 61,336. Astatic 4-Coil Mirror Galvanometer after Du Bois and Eubens, Figure, with i £ s. d. 4 coils each of 20 ohms; one massive magnet system with rotary mirror, about 1 gramme in weight, 1 medium-heavy magnet system 0.25 g weight (Electrot. Ztschr., 1894, p. 321; cf. Gan.-Man., Fig. 761; Gan.-Bein., Fig. 832) 22.10.0 The following should be ordered separate for above: 61.337. Protecting Case ................ ' 61.338. 1 Light Magnet System, approx. weight 0,1 g 61.339. 4 Coils of each 2000 ohms 61.340. 4 Metres Quartz Fibres in wood case 61.341. 1 Shunt Resistance, l/9, l/,,g, V«» the galvanometer resistance The preceding instrument is of extraordinarily high sensitivity. 61.342. Mirror Galvanometer after Thomson-Szymanski, Figure, with astatic magnet- system and directing magnet, with wire connecting blocks for putting the coils in parallel, in two groups and in series (cf. also Gan.-Man., Fig. 761; Gan.-Eein., Fig. 832) . . The four coils have a resistance of 4 ohms each. By removing the front wall the galvanometer can be opened and therefore easily and quickly adjusted. The instrument is highly sensitive and is very suitable for experiments with thermo-electric currents, for telephone currents, and for demon- strating i hi' ruiTcnts on cutting the lines of force. The case is of mahogany. 61.343. Wall Bracket for above with lens and Glow Lamp for 110 — 220 volts, Figure, for enabling the instrument to be used as a reflecting galvanometer ........ The voltage should be quoted in ordering; if not stated we supply a 110 volt lamp. 61,344. Extra Price for a Nernst Lamp, which gives a bright luminous pointer. 110—220 volts only For D. C. 61,345. Fixing Device for suspended board No. 50,119, Figure, also rotary arm with lens and scale-lamp. Price without suspended board By means of this device the galvanometer is firmly fixed on the suspended board, but in such manner that it can be easily set up by adjusting the three levelling screws. The illustration shows a suspended board No. 50,119 with a Deprez-d'Aisonval Galvanometer No. 61,389 with mirror reading used as a Reflecting Galvanometer; illumination by a single filament electric lamp and with the above fixing device and rotary arm for the lamp. The device can, how- ever, also be used with Galvanometer No. 61,342 and similar ones. As regards voltage etc. the same remark applies as in No. 61,343. <>!..!!(>. Multiple Commutator for placing alongside the Lecture Table, for enabling the coils of Galvanometer No. 61,342 to be put in parallel, series, and in two groups, F i g u r e, without conned ing leads 1. (I. O 1. 10. 0 5. 0. 0 0. 8. 0 5. 0. 0 6. 0.0 2. 5.0 0. 8.0 2. 0.0 3. 0.0 56* 884 Voltaic Electricity. Section 3: Electro- Magnetic Current Measurements. No. in :;t: 61 347 A. 1:5. 61 347 B. 1:5. 61 354. 1:6. 61,347. Iron-Clad-Galvanometer after Du Bois-Kubens, Figures A and B (Ztschr. f. In- £ « (1 strumentenkunde, 1900, p. 65), with a light and a heavy magnet suspension with plane mirror, two pairs interchangeable internal directing magnets, one pair external directing magnets and two coils of 2000 ohms each in cast steel sheath, with spherical sheath as a second magnetic shield and cast steel cylinder as third magnetic shield 37.10.0 Fig. 61,347 A shows the outside appearance in conjunction with an anti-vibration suspension No. 61,357; Fig. 61,347 B illustrating the instrument with the second and third shield removed. This type of galvanometer is constructed in view of the disturbing magnetic influences of 1 electric tramways; the steel envelopes have a strong protecting action against these influences. Each suspension is supplied packed in a small box with a plane mirror. 61,348. Iron-Clad Galvanometer after Du Bois-Eubens, as No. 61,347,-but with eight terminals and one pair of coils with differential winding each of 2 x 1000 ohms in cast steel envelope 1 1 . 61,350. 61,351. 61,352. 61,353. Accessories and Spares for Nos. 61,347 and 61,348: 61,349. 2 Coils each of 5 ohms in cast steel sheath <>. 2 Coils each of 100 ohms in cast steel sheath •>. 2 Coils with differential winding each of 2 x20 ohms, in cast steel sheath 7. 1 Light Magnet Suspension including Mirror, 35 mg 1. 1 Heavy Magnet Suspension including Mirror, 165 mg .' 1. 61.354. Metal Stand, with glass bell, Figure, for suspending the magnet stirrups 0. 61.355. 1 Small Box with 10 Quartz Fibres on mirror base o. Shunt of Copper Wire for the coil resistance of 2 x2000 ohms: 61.356. 1/9. Vti. Vt.i «- 61,356 a. 1/9. V.9, V,.., V..» ....-• 7. 61, 356 b. V,9. V* I/ I/ /49> 19 Id. 5.0 10. O 10. O !.->. ii ,-). I > 13. O IS. o :.. 0 o o 1.-.. n 10. O 61,357. Arrangement for the anti-vibration suspension of the Du Bois-Rubens Iron-Clad Galvano- meter, as suggested by Hagen 6. t». 0 The device, like that of the Julius method, is fitted directly on the east steel cylinder; when ordering, the iron-clad Galvanometer should be sent us or the instrument should be ordered together with the device. Moving Coil Galvanometers. The generally recognised advantages of the Deprez-d'Arsonval Galvanometers with fixed magnet and moving coil are: independence of external magnetic influences; good damping and insensitivity to rough treatment render the instruments specially suitable for educational and practical purposes. We are therefore including in the following pages an extensive selection of these instruments. 61,358. Portable Moving Coil Needle Galvanometer, with hand suspension for the coil. F i g n t e. suitable for /,ero methods (Whcatstone Bridge and t lie like) and for stii' exercises. 1'. KM) approx. resistance 150 ohms; 1 degree deflection approx. 1 -10 '; amps. 61,350. -- idem, arranged for hanging on the wall 3. 15.0 (1. .-,11(11. •.'SHIP. -JU . in :t74. Moving Coil Needle Galvanometers. 885 61 362 A. 1:5. 61 362 B. 1:5. 61.360. Portable Moving Coil Needle Galvanometer, Figure; approx. resistance 150 ohms; 1 degree deflection = approx. 0.000 006 amp 61.361. Portable Moving Coil Needle Galvanometer after Weston, Figure, of very high sensitivity, completely replacing a mirror galvanometer for technical resistance-measu- rements and other zero methods; approx. resistance 300 ohms; 1 degree deflection = approx. 5xlO~7 amp. The coil rests on pivots and the instrument does not there- fore require any special setting up 61.362. Precision Moving Coil Universal Galvanometer, Figures A and B, for the direct measurement of currents to 0.15 ampere, voltages to 150 volts, e. m. f.'s, battery and wire resistances from 0.03 to about 30,000 ohms, and for determining errors' in leads: comprising a precision Millivolt- and Ampere-Meter of 1 ohm resistance and a spheri- cally stretched measuring wire the graduations of which permit of the resistances being read direct. By using a 110 volt battery insulation resistances to approx. 1,000,000 ohms can be measured. For measuring currents above 0.15 ampere the undermentioned shunts are used. A carrying case is included in the price; there is room for 4 shunts in the case . £ 3. 5. d. 0.0 8. 5.0 21.15.0 The scheme of connections together with explanatory signs in German (or if desired, in French or Russian) are etched into the cover plate of the instrument. Accessories for No. 61,362: Manganin Shunts for placing on the instrument: 61.363. For Currents to 0.75 Ampere 61.364. „ „ „ 1.5 11.365. .. „ „ 3 <>!.. •!(;<>. „ „ „ 7.5 61.367. „ „ „ 15 61.368. „ „ ,, 30 Manganin Shunts including leads for connecting to the instrument: 61.369. For Currents to 75 Amperes 0 15. 0 0 15. 0 I) 15. 0 I) 19 0 0 19. 0 1. 1. 0 61,370. 61.371. 61,372. 61,373. 61,374. 150 300 750 1500 3000 ) with leads 0.2 long \ with leads 0.75 m long with leads 2 m long . 2. 2. 7. 9. 4. 0 6. 0 5. 0 I). 0 0. 0 |. .-.KI7, 2386, 2372, 2:!7.'l. 21. lo. i» 238:5. 886 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. No. til 375- 61 384. 1 : 5. 61 385. 1 : 8. Manganin Series Resistances: £ s. d. 01.375. With \ section for 300 volts 2. 10. 0 61.376. „ 2 sections for 300, 450 volts 3. 16. 0 61.377. „ 2 „ for 300, 750 volts 6. 0. 0 61.378. „ 3 „ „ 300, 750, 1500 volts lo. n. n 01.379. Shunt Plug, */» ohm, for converting the comparing resistance from 1 ohm to 0.1 ohm n. ]:,. i> (i 1,380. Resistance Plug, 300 ohms; for putting in circuit as a safety resistance in the measurement of battery resistances 0. in. n 61.381. Battery Box with 72 Dry Cells, in 6 compartments with 4 cells eaih and 4 compartments with 2 cells each, with terminals for each compartment 7. 1". u 61.382. Induction Coil for generating A. C. for measuring electrolytic resistances (Kohlrausch1 method), for connecting up to from 1 to 2 dry cells 1. l."i. n 61.383. Telephone for use in measurements with preceding Induction Coil | 0. 8. 0 61.384. Projection Moving Coil Galvanometer, Figure, on adjustable stand 4. 0.0 The galvanometer proper is completely enclosed in a mahogany box and the long horizontal needle plays between two glass plates one of which is provided with a projection scale. This very sensitive instrument is intended to be used with the projection lantern and is put in circuit by pressing a button on the top of the apparatus. Needle Galvanometers with moving Coil: see below, under the Technical Measuring Instruments. 61,38."). Model of a Moving Coil Galvanometer with Bifilar Suspension, F i g u r e, after Friedr. C. G. Mtiller (M. T., Fig. 185) 1. 16.0 61.386. Model of a Moving Coil Galvanometer after Kolbe, Figure (Kolbe-Skellon, Introduction to Electricity, Part 11, Fig. Ill), very compact instrument with scale visible at a distance; can also be used for zero methods 3. ."i.o 61.387. - - idem, larger and more sensitive 5. 0. 0 61.388. Galvanometer after Deprez-d'Arsonval, Figure, with mirror and needle reading, on ebonite base-plate with glass bell (\V. und K. phys. Prakt., Fig. 27!>; (Ian. -.Man., Fig. 762; Gan.-Kcin., Fig. 897), witli polished plane mirror 8. 0. l» 61.389. -- idem, for mirror reading only, without needle 7. in. o 61.390. Galvanometer after Deprez-d'Arsonval. with mirror reading, on tripod stand, F i g u r e (W. u. K. phys. Prakt., Fig. 280), with polished plane mirror 7. 1 .">.(» The following are given in: 1 steadying resistance, 1 pair vibrating weights for ballistic purpo.-es and 2 damping suspension frames. Sensitivity at I in scale-distance: I nun deflection with approx. 1x10 H amp.: resistance of coil, approx. 250 ohms. The time of swing without weights is about d seconds, with weights about 15 second-. <>1,3!»1. Moving Coil Mirror Galvanometer after K. \\iedemann. Figure, with 3 different interchangeable coils; a very neat instrument and highly sensitive 7. .">. 0 ' 'oil I has a resistance of approx. 100 ohms. Coil II of approx. 20 ohms; Coil III is formed of .'!..") turns of 1 mm thick wire. The instrument is covered off on both sides by plate glass which can be raised up for I lie insertion of rubber coils. The sensitivity is, when Coil I is used: 1 mm deflection at 1 in scale-distance approx. 3xlO-» amp.: with Coil II approx. lxlO-s amp The duration of the full period of swing is about 15 — 20 seconds. ri. 395. 4507. No. 61393. Moving Coil Mirror Galvanometers. 887 61 386. 1 : 6. 61 388. 1 : 4. 61 390. 1 : 5. 61 392. 1 : «. •For using Xos. <>1,3S8 — (il.391 as a Reflecting Galvanometer the Accessories listed in connect ion with No. 61,342 are employed. £ s. d. 61.392. Reflecting Moving Coil Galvanometer, Figure (German design), with rotary arm for lens and glow lam]) (Ztschr. f. d. phys. u. chem. U. 22, p. 138). Price with single filament glow lamp of 110 — 220 volts pressure I 8. 5. 0 This galvanometer has been specially designed by us for lecture purposes and has the following ad van - t i- -: (1 ) simplicity and complete comprehensiveness of the cons traction. (2) High sensitivity with light treat- ment. (3) Two groups of turns of different resistance on the same moving coil; the galvanometer can conse- quently be iis"d for all purposes with advantage without the coils first having to be changed, and the, damping can be easily regulated. (4) The period of swing can be easily increased for ballistic purposes. (5) The instrument can be conveniently set up and adjusted as a Reflecting Galvanometer. The galvanometer has one group of turns of approx. 100 ohms (1 mm deflection at 1 in distance = approx. 1 xlO-8 amp.) and a second group of turns of approx. 10 ohms (1 mm deflection at 1 m distance = approx. 3 xH)-H amp.). The duration of the complete period of swing is 10 seconds without weights and about 18 seconds with weights. Complete description sent on application. 61.393. --idem, with Nernst Lamp (can only he supplied for 110—220 volt D. C.) . . 8.10.0 Unless otherwise stated, Lamp is supplied for llO volts. Accessories: see Nos. 61,313, 61,314, 50,121, 50,119, 50,122, 50,123, 50,124, on p. 879. Cl. 5107, 2375, 237(!, 2378, 5!>'J4. 888 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. No. HI ::'.il - 61 394. 1 : 6. 61 395. 1 : 6. 61 396. 1 : 6. 61 397. 1 : 10. 61 398. 1 : 4. 61.394. Universal Shunt connected up by Ayrton's method, for No. 61,392, F i g u r e, also £ suitable for other Galvanometers of 100 ohms max. resistance; total resistance 10,000 ohms with stages of 1, 1/10, 1/100, Viooo> Vioooo- The ratio of damping therefore remains approxi- mately constant 3. n. o 61.395. Connecting Switchboard for No. 61,392, Figure, for regulating the sensitivity and damping 3. I. o The variation of sensitivity cannot, of course, be measured in this instance, but can easily be i manipulated so that the device is very practical especially for zero methods. 61.396. Simple Moving Coil Mirror Galvanometer, for school use, Figure; approx. resis- tance of coil, 20 ohms 1. 10. 0 61.397. -- idem, with Reading Telescope, Figure, for firmly fixing, preferably to a wall between two windows 3. '). () 61.398. Moving Coil Mirror Galvanometer after Ayrton-Mather, Figure :>. o. o As a rule the resistance of the coil is about 325 ohms. If desired we can supply, in place of this, cods with other resistances, e. g., about 14, 95, 1000 ohms or any other values. Coils of 325 — loon ohm-- are charged £ 0. 10, 0 extra. In ordering it should be stated whether the coils arc to be used aperiodi- c-ally or ballistic-ally. The coils together with suspension can be, interchanged forthwith, cf. Fig. (i 1.399. The time of swing of the ballistic coils is about .'! seconds. The chief advantage of these Calvano- meiers is their simple, massive construction and ease of manipulation. The sensitivity at .'i2."> ohms is: 1 mm at 1 m distance =•- approx. 2xlO~8 amp. Interchangeable Coil together with Tube Suspension, F i g u r e, for preceding ('.ah -anomeier, aperiodic or ballistic construction. List No. 61,399 61,400 61,401 61,402 Approx. Resistance 14 95 .">l'."i l(KM) ohms £ 2.0.0 2.0.0 2.0.0 2.10.0 61,403. Moving Coil Mirror Galvanometer after A\ rion -.Mather, specially constructed for school use, Figure 6. <». (i This iralvanoineter is arranged so that the outer covering can lie reinoM-d lor showing thu internal construction. As regards resistance of the coils, sensitivity and prices of -pan il>. the same remarks applies as in No. (il .3!)S--(il .402. cl. .-.Till, .-.IIP.'. 55I7, 5508, 5384. No. fil 407. Moving Coil Mirror Galvanometers. 889 61 406. 1 : 5. 61 407. 1 : 6. 61,404. Mirror Galvanometer after Ayrton-Mather Type No. 61,398, with three interchangeable coils, 1 aperiodic coil of 30 ohms; one 325 ohm coil, aperiodic; one 1000 ohm coil, ballistic; in mahogany carrying case The Ayrton-Mather Type Galvanometers are, unless otherwise stated, arranged for objective reading and 2 metres scale distance, which permits of reading by a telescope at about 3.5 in distance. They can also if necessary be provided with a plane mirror for telescope reading at any distance. 61,40F>. Galvanometer after Ayrton-Mather Type No. 61,398, with arrangement for reading by lamp and scale for zero methods, Figure, for fixing to the wall. In spite of the small scale distance and small amount of space necessary, the sensitivity is increased by interpolating a cylindrical mirror Unless otherwise staled, the singl" filament glow lamp pertaining to the instrument is supplied for 110 volts £ s. d. 9. 0. 0 8. 0. 0 61.406. Laboratory Galvanometer after Ayrton, with moving coil, Figure, for fixing to wall. The instrument is always ready for use and takes up but little room. With 600 ohms resistance 1" deflection = approx. 3xlO~N amp \ 9. 0. 0 61.407. Moving Coil Mirror Galvanometer for fixing to wall, Figure, very simple and practical type; sensitivity: 1 mm at 1 in scale distance and 300 ohms resistance = approx. 6xlo-!P amp 5. 0. 0 Cl. 2383, 5385, 5329, 2334, 5078. 890 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. \0. fil 61 407 and 61 409. 12. 0*0 0*0* <> 1 W ".s» 61 412 A. 61 411. 1 : r. 61 412. 1 : 3. 5. o.o 61.408. Simple Reading Telescope for preceding, for fixing direct on galvanometer, similar £ to Fig. 61,397, p. 888 J. 10. 0 61.409. Objective Reading Device for Wall Galvanometer, Figure, for fixing to roof, illuminated by a glow lamp; scale 0.5 m long, with vertical adjustment: without leads 1. 10. n The apparatus on which measurements are to be taken can be set up on a table immediately below the reading device, thus saving a good deal of room. The galvanometer deflections can conve- niently be observed. The galvanometer must have a concave mirror. 61.410. - - idem, with Nernst Lamp, giving a veiv briirht image, suitable only for 110 to 220 volt D. C Unless otherwise ordered, Nos. 61,409 and 61,410 are supplied for IK) volts. 61.411. Moving Coil Mirror Galvanometer for demonstration purposes. Figure, with two different groups of windings on the same moving coil, one of which can lie used for damping; also with arrangement for increasing the period of swing for ballistic purposes; including fixed damping resistance The sensitivity is: for the group of turns of approx. 100 ohms: 1 nun deflection at 1 m = approx. 4 xlO-'-' amp.; for the second group of 10 ohms, approx. 4 xlll - amp. The duration of the complete period of swing without weights is approx. 6 seconds: with weights, approx. !."> second-. For using this galvanometer as a reflecting instrument, the bracket, etc. listed under No. »>1,342 is suitable. n. 49: with windings which 61416 2x300 „ 6 » i> „ 4 xlO-9 18. 5. 0 J cannot be used separately. 61,417. Extra Price for Oil Damping, for enabling the instrument to be used at places which an- not anti-vibrating 6 1.4 is. Extra Price for Xos. 61,412 — 61,414 if provided with arrangement for increasing the l>crind of -wing to approx. 15 seconds for ballistic purposes 1.13.0 0. 18.0 6 1.4 in. Extra Price for Xos. 61,415 and 61,416 for two entirely separate windings which can be connected up in any desired manner 1. 2.0 til. 42d. Extra Price for a Mirror Chamber with Telescope the axis of which is placed at 45° to the mirror plane 4. 10. 0 61,421. Extra Price for a Telescope with Scale on turning arm which can be extended to V-2 metre 4. 0. 0 tii.122. Large Einthoven Electro-Magnet String Galvanometer, improved type, Figure. very sensitive with extremely short period of swing. Price without microscope . . . 47.10.0 A silvered quartz fibre of high resistance is stretched between the cimeiformly pointed pole pi'-ei-s of a powerful electro -magnet. The current-sensitivity of the instrument can be varied by regulating the voltage. The deflections of the quartz fibre traversed by the current in the magnetic- field can be observed through a microscope let in through the holes of the pole pieces. The instrument is of anti-vibration type and independent of external magnetic influences, and possesses a very short period of swing. It in suitable for a large number of fine measurements, e. g. : (1) determining the conductivity of the air produced by uranium and radium preparations; (2) mea- suring currents produced by atmospheric electricity; (3) ballistic measurements of small quantities of • •l"<-trieity: •: 4 ) measurements on telephone currents and nerve currents. Arrangements for registering on s'-nsitive paper can easily be adapted to the instrument. With a magnification of x 1000 and employing the thinnest quartz fibre, the following sensi- tivity can be attained: 0.1 mm = 1 xlO->2 amp. A correspondingly lower sensitivity is obtained with the use of platinum, gold, silver, and copper wire. Further particulars of these on application. Cl. 30 F. 892 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. No. til (•_•:; 61 441. 1 : 0. 61 443 A. 1:7. 61 443 B. Zeiss Optical Apparatus for No. 61,422. 61.423. Achromat A 1 61.424. Achromat A with iris diaphragm 2 • 61.425. Achromat AA 1 61.426. Achromat C 61.427. Achromat DD 61.428. Micrometer Ocular 3 graduated over the entire field of view 61.429. Projection Ocular No. 2 61.430. Projection Ocular No. 4 61,431. Small Permanent Magnet String Galvanometer, Figure, with simple microscope for direct reading with micrometer ocidar of approx. magnification of 60, including case 9. 5.0 This small simplified string galvanometer is very practical for many experiments where the maximum sensitivity is not required. It can be also used for projection for photographic recording and if desired is arranged to fit the optical bench of a projection lantern. Further particulars on application. With quartz fibre (approx. lo.ooo ohms resistance) and a magnification of 100 the following sensitivity can be reached when adjusted aperiodically : 1 mm deflection = 8 x!0~7 amp.; with cxtra- aperindic adjustment 1 mm = 3.2xlO~10 amp.; with 140 ohm gold fibres the corresponding sensi- tivities are: 7.5xlO-8 and 3xlO~8 amp. t;i,.|32. Small Electro-Magnet String Galvanometer, Figure, with simple microscope as in No. (il.131 13. 0.0 The sensitivity is about 3 — 4 times as great a« in No. 61,431. Photographic Recording Apparatus and other Accessories for String Galvanometers quoted for on application. (il.133. Alternating Current Reflecting Galvanoscope after \\einhold (\\. I)., Fig. 5X8) . . 2. o. o < 1. :u>, 3.'i>. '.'389, SIM, .'illlli. s. (1. i'. o 0. ii 13. (I 13.0 15. o 3.0 4.0 4.0 Nil. lil 444. String Galvanometers. Shunts. 893 61 444. 1 Shunts for Mirror Galvanometers. £ 8. d. Galvanometer Shunts, Figure, for varying the sensitivity : For 1 Galvanometer with a Kesistance 61,438. 61,439. 61,441. to 1 Ohm 100 Ohms 100 1000 Eeduction of Maximum Sensitivity to 0.1 0.01 2. 0.0 , 0.1 0.01 0.001 12. 10. 0 0.1 0.01 0.001 0.0001 . 3. 0.0 Shunt Resistances Nos. 61,438 — 61,441 have a short circuit plug. The resistance coils are wound on copper and connected up in such manner that 1/9, 1/99, 1/99e etc. of its resistance is connected in parallel with the galvanometer. These shunts are therefore chiefly suitable for Moving Needle Galvano- meters, as they do not give constant damping with Moving Coil Galvanometers. When ordering, the resistance of galvanometer should be quoted. 61,394. Universal Shunt connected up according to Ayrton's method, Figure 61,394, p. 888, for Needle Galvanometers and Moving Coil Galvanometers; damping ratio appro x. constant; suitable for all galvanometer resistances up to 100 ohms; total resistance 10,000 ohms; stages, 1, 1/10, Vioo> Viooo? Vioooo! constructed of manganin 3. 0. 0 61.442. --idem, total resistance 100000 ohms, for Galvanometers up to 1000 ohms resistance 61.443. Power Shunt after Prof. Kommerell, German Design, Figures A and B (Ztschr. f. d. phys. 11. chem. U. 22, 1909, p. 13) The object of the power shunt is to enable sensitive Mirror Galvanometers to be used not only for their original purposes — demonstrating and measuring very small currents — but also for measuring currents to about 15 amperes. Fig. 61,443 B shows the connections of the apparatus. Complete description forwarded if desired. Reading Devices for Mirrors Instruments. The angle of rotation of Mirror Instruments is measured either in a subjective manner, in accordance with Poggendorff's suggestion, with the aid of a Telescqpe and Scale, or, in an objective manner, by projecting the filament of an electric, glow lamp or the shadow-image given by a wire stretched in front of a brilliantly lighted aperture, on to a scale. In the first case the rotating mirror must be a Plane Mirror; in the second case either a Plane .Mirror with projection lens in front, or a Concave Mirror, is used. 61.444. Simple Reading Telescope with paper scale, Figure, for" schools and exercises , The Telescope is fitted with a 24 mm diameter objective and cross wires; it has a vertical adjustment and can rotate about the horizontal and vertical axis. 4. 10.0 9. 0.0 5.0 Cl. 239.1. 894 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. NIL Ill I I • - 61 449. 1 : G. 61 448. 1 : 0. 61 446. 1 : 6. Reading Telescopes with Universal Scale Holders (but without Scale), Figures. List Xo. Objective Aperture mm 10 15 Magnification Price Remarks 1 S. (]. 61,445. 61,446. 61,447. 61,448. 61,449. 61,450. 61,451. 61,45'J. 61,453. 61,454. 61,4:.:). 61,456. 61,457. .6 £3.15.0) Telescope without Rack, I'ni- 12 £ 4. 5. 0 ) versal Scale Holder without fine adjustment. 20 16 £ 5. 10. 0 I Telescope with Rack, Uni- 25 16 £ 6. 5. 0 versal Scale Holder without 30 20 £ 7. 5.0 | fine adjustment, 25 16 £ 10. 5. 0 ( Telescope with Rack, Uni- 30 20 £11. 0.0) versal Telescope Holder with micrometer tip motion. Telescope with Rack, Tni- 30 20 £ 12. 10. 0 ) versa! Telescope Holder with 40 L'ti £13.15.0 ) fine adjustment in vertical direc- tion as well as about two hori- zontal axes. Telescope with Rack, Uni- 20 16 £ 9. 5. 0 I versal Telescope Holder with 25 16 £10. 0.0 I micrometer tip motion. The 30 20 £10.15.0 I illustration is not exactly in 40 26 £11.15.0 I accordance with the construc- tion. No. IU.448 is (contrary to the illustration) supplied with Telescope having rark adjustment. The scalea -uitable arc Nos. 61,458 — 61,475. Wood Scales with T-shaped cross section, of old, dry material, with narrow paper strip, accu- rately graduated by means of the dividing engine when first obtained, with mirror figures, when ordinary figures are not expressly desired. A) Graduated every 2 Millimetres*) Length mm loo List No. 61,458 £ 0. 6. 0 I?) Graduated in Millimetres: List No. 61,462 t 0.7.0 *) Can be highly reeiuimnMid'-d for low magnification l!":i(lini; Telrsropr>. (ill!) 61,459 0.8.0 61,463 0.9.0 800 61,460 0. 10. 0 61,464 0. 11. 0 1000 61,461 0. 12. 0 61,465 0. 13. 0 (1. 5697. No. 01 480. Reading Telescopes. 895 61 452. 1 : 6. 61 454. 1 : 12. 61 478 — 61 480. 1 : 5. Plate Glass and Milk Glass Scales, manufactured of glass plates specially prepared for this purpose and plane polished on both sides; with finely etched millimetre graduation and mirror figures. £ s. (1. Length mm List No. Plate Cilass £ List No. Milk Glass £ 400 61,466 0. 17. 0 61,472 0. 18. 0 600 61,467 0. 22. 0 61,473 0. 23. 0 800 61,468 0. 28. 0 61,474 0. 30. 0 1000 61,469 0. 33. 0 61,475 0. 38. 0 1200 61,470 0. 40. 0 61,476 0. 50. 0 1400 61,471 0. 46. 0 61,477 0. 60. 0 The scales are also made in other lengths and if desired are figured throughout or, commencing from the centre, coloured red in one direction and black in the other, and are also provided with figures for direct reading. If desired, the plate glass scales are supplied slightly ground in order to illuminate the graduation from the back or for enabling them to be used for objective reading. The Milk Glass Scales are used permanently in a number of Laboratories on account of their brilliancy. Devices for Objective Reading in Lecture Rooms, i. e., for Reflecting Galvanometers: see Nos. 61,310—61,316, p. 879; Nos. 61,343—61,345, p. 883. Reading Telescope, Figure, adjustable horizontally and vertically, or simply micrometri- cally. The celluloid scale is fitted under the telescope; ocular extension movable by rack. List No. 61,478 61,479 61,480 Objective Diameter 27 33 40 mm Magnification 16 23 27 times £ 7.10.0 9.5.0 11.10.0 For illuminating Scales we recommend 2 Table Lamps No. 50,114, p. 21, at £ 0. 18. 0 each. Stands for setting up Reading Telescopes: see Nos. 51,12") — 51,131, p. 205. CM. JG9S, 2393, -':!!J7. 896 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. Nil. HI 480 a — 61 481. 1 : 0 61 480 a. 1 : 10. 61 483. 61,480 a. Simple Lamp Reading Apparatus, with puniffin lain]), Figure 61.481. Lamp Reading Apparatus, for objective reading, Figure, with single filament glow lamp together with switch and plug contact The scale is adjustable vertically and has a lateral motion with fine adjustment. A rending mirror permits of a number of observers reading simultaneously without error. 61.482. Lamp Reading Apparatus with Nernst Lamp and slot diaphragm, F i g u r e, with switch, 2 metres lamp flex., plug contact and plug; for 110 — 220 volt 1). ('. only. . Lamp Reading Apparatus for fixing to Ceiling: see Nos. 61,409 and 61,410, p. 890. 61.483. Lamp Reading Apparatus for objective reading, Figure, on wood stand, with electric glow lamp and pliable Celluloid Scale, adjustable vertically The light from the lamp falls on a universal motion mirror. It is piojectcd thence on to the mirror of the measuring instrument through a rectangular aperture acnnss which a vertical thread is stretched. When the lamp reading apparatus is properly set up a strongly illuminated spot appears on the transparent celluloid scale, a fine black line appearing in the centre of this spot. l.y means of a screw the scale of the apparatus can be moved along its length in order to adjust the lim line on the zero point of the scale. The scale can be spherically curved or stretched straight. 61.484. -- idem, with NeriiM Lamp, for I). ('. of 110 — 220 volts only •">. 61,4X.~>. -- idem, with incandescent gas burner I. 61.486. --idem, with paraffin lamp. Figure '• 61.487. Extra Price for a Stand for Nos. (il. is:!— (iljsii lor placing on the floor. V \ g u re 1. 61.488. Lamp Reading Apparatus, Figure, as No. t;i.is:i, but without Lamp I- Items Nos. 61,310—61,315 can be used as Lamps for above. I'nlcss otherwise stated, the apparatus arc supplied with 111! volt lamps. Lamp Reading Apparatus Nos. 61,481 — 61,488 for objective reading require a Con- cave Mirror on the apparatus to be read the radius of curvature of which is equal to the scale distance. In all cases a Plane Mirror with projection lens can be used in front of them. Suitable lenses for the individual instruments quoted on application. < i. iioi. 4:11--', 2403. N<>. lil 489. Glow Light Oscillographs. 897 61488. 1:10. 61486 and 61487. 1 : 12. 61 489 A. 61 489 B. Demonstration and Graphic Reproduction of Current Curves. <; 1.489. Glow Light Oscillograph Tube, Figure, after Gehrcke-Buhmer, for demonstrations and investigations, comprising oscillograph tube and stand 2. 10. 0 Two axially arranged electrode wires are enclosed in an evacuated tube divided by an insulating partition. The predominating cathode is covered over by a bluish glow at intervals when the current flows through, this glow being proportional to the momentary current. The curve shape is rendered visible by the aid of a rotating mirror and can be photographed when a certain rotational velocity is imparted to the mirror. The velocity of the mirror can easily be made to suit the current-frequency predominating. The tube can be used in a horizontal position for cinematographic photos. Pig. 61,489 A shows a photograph of an A. C. curve, and Fig. 61,4898 that of a condenser discharge. If desired, and at an increased price, tubes can be supplied of quartz or Uviol glass. Cl. 3524, 5820, G009, 3540, 3541. 898 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. No. 61 490- 61 490. 1 : 10. 61 491 and 61 496. 1 : 6. 61 493. 1 : 8. 61 499. 1 : 6. -•'ft' 61 500. I : 9. 61502 and 61499. 1:8, 61.490. Rotating Mirror Box driven by a handle, Figure The mirrors of the box are of the best possible quality. If desired they can be supplied coated with silver or platinum on front at a proportionately higher price. 61.491. - - i d e m, driven by a 110 volt D. C. Motor, F i g u r e, with rheostat, but without arrangement No. 61,496 shown in illustration 61.492. The Motor c;in also be supplied for 24, 65, 150 and 220 volts I). ('. Extra price The working voltage should be given when ordering. 61,49.''.. — idem, driven by a synchronous A. (\ Motor. Figure When ordering, kindly state working voltage and frequency. 61. 1!H. - idem, with clockwork drive. The speed can be regulated within wide limits liv means of a centrifugal regulator 61,49."i. Transformer t'n r transforming the A. C. to be investigated to the high voltage necessary; for 100 — 120 volts primary and .">(> cycles When ordering, kindly quote voltage and frequency. i i. M £ s. d. 2. 10.0 (i. 10. (I (t. 10. 0 7. <>. o :.. in. o 3MJ, No. 61 504. Oscillographs, Braun Tubes. 899 61 503 a. 1:8. 61,496. Arrangement on the mirror for alternating charges and discharges of Condensers, for £ »• d. observing the charge and discharge curves, Figure j 1. 15. 0 61,497. Falling Slide for cinematographic photos. Price according to size of plates £ 3. 0. 0 to 61,499. Cathode Ray Tube after F. Braun, Figure The mode of action of this vacuum tube is based on the fact that a cone of cathode rays supplied by an influence machine or a rapidly working spark coil (the rays being restricted by a narrow diaphragm) produces on the glow screen, which is coated with phosphorescent paint, a spot which is as small and bright as possible, the behaviour of this spot being observed through the glass and mica. If a small magnetizing coil, the axis of which is placed fairly vertical to the tube, is slipped along the tube, and a current allowed to traverse the latter, the cathode rays are deflected. If in addition an A. C. is used, the spot of light is set into synchronous vibrations. If now a rotating mirror is placed opposite the tube, the light spot is dissolved for the purposes of the curve. Ample means are therefore available for studying the rapid variations of a magnetic field as well as the secular course of such fields. The current curves of A. C. generating stations are adapted for such observations, as well as the curves of the primary an secondary circuits of an induction coil. For suitable mirrors see Nos. 61,490 — 61,494. The rotation of the luminous point in magnetic rotating field is specially adapted for demonstration purposes (of. List Nos. 61,503 and 61, 503 a). 61.500. -- idem, larger, Figure, 1m long, with screen 130 mm diameter . 61.501. -- idem, after Braun-Wehnelt, Figure, for electrostatic deflections 61,502. Two Coils on Stand, Figure, one arranged to rotate The luminous point describes Lissajous's and similar curves if alternating current is conducted through two coils placed on the diaphragm of the Braun tube. By rotating one of the magnetizing coils, and thereby altering the angle enclosed by the two coils, the various figures are obtained. If current from a central station is employed, a glow lamp resistance must be placed in series (see N.I. 61,504). (!!,. ")().5. Magnetizing Ring for Two-phase Current, fitting the stand of preceding apparatus. Price without stand . . 61,50.'! a. - idem, for .'{-phase current, Figure, without the retort holder illustrated and without stand . c.l.r.o.'l l>. Stand for Xos. 6 1.503 and 61,503 a ('.1,504. Glow Lamp Resistance Tiiis resistance consists of 4 glow lamp holders each with two current terminals, mounted on a slate slab. It is used when apparatus Nos. 61,502 — 60,503a are to be worked connected direct to a network. 6. 0. 0 1. 0. 0 3. 0.0 1. 15. 0 1. 10. 0 1. 16. 0 1. 16. 0 0. (i. 0 1. 4. 0 Cl. 2740. 900 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. N.I. 61 ;,n.-i — 61 505. 1 : 6. 50796, 61505, 61507, 61509, 61510, 61511. 1 : 6. 01,5(1."). Demonstration Double Oscillograph with two measuring loops, after AVehnelt, Figures (E. T. Z., 1903, p. 703 and 1904, p. 416), on stand Between the poles of an electromagnet excited by D. C., a loop of hard drawn silver wire carries a glass mirror. If this moving system is traversed by fluctuating, pulsating or oscillating currents, and pro- vided that the apparatus is arranged as in above illustration, luminous curves, corresponding to the current curves, are projected on to a screen placed opposite the projection lantern. If now the moving systems of the double oscillograph are connected in parallel on an A. C. network, the current curves can be made to coincide exactly. If now by means of the switch apparatus No. 61,510 a non-inductive re- sistance, then an inductive resistance, and finally a capacity — or the two latter simultaneously -- are put in series with the moving system of one of the oscillographs, the resultant current reductions and phase lead and lag, or in other words, the phase displacement between current and voltage, can be shown in a very pretty manner. We send complete description on demand. For Rotating Mirrors see N'os. 61,490 — 61,494. Ol,:>lo. NEW! Switch Apparatus (German Design) for producing Phase Displacements with leading and lagging current, Figure. Price without lantern or other accessories illustrated The apparatus consists of a marble slab on mahogany frame, two non-inductive resistances, one sliding resistance, one coil with large, adjustable self induction, one change-over switch, and the necessary terminals for 'connecting a capacity, the oscillograph and the A. C. source. s. 61,507. Diaphragm with two holes, fitting projection lanterns (1. 0. (I 61,511. Condenser insulated with paraffined paper, about 12 mfd., for voltages to 120 61,512. Photograph on glass of the scheme of connections of the double oscillograph in con- junction with Switch Apparatus No. 61,510 0. 6. 12. 0 0. 10. 0 61.508. Screen with clamp, for screening the secondary radiation i 0. 0. o 61.509. Large Lens on Stand 0. 16. 0 2. 14. 0 1. c> 01. 500. Oscillograph after Wehnelt, with a metal loop . 3. 0. o specially adapted for investigating and demonstrating the curve of the ;irc of A. C. arc lamps and the influence of the choking coil on the same, for checking the working of interrupters etc. ill. .">!:'>. Oscillograph after \Vittmann, with a metal loop, Figure 11. o. o The oscillograph IKUS converging pole pieces the distance apart of which can be varied. A small ebonite frame is placed in the air gap, which is about 4 mm wide, a current loop of tinsel being stretched across this frame. The loop is conducted over a small ivory pulley and can be evenly adjusted by micro- metrical arrangement. For damping the oscillations of the loop itself, use is made of a very light aluminium frame which is insulated and cemented on to the loop. The electromagnet is arranged to rotate about a vertical a*is so as to render it possible to place the loop vertically. The apparatus is used in the same manner as the Wehnelt Hscillographs. the present instrument however being much more sensitive Cl. 2740 ', 4957. Xo. 61 522. Oscillographs. Ammeters and Voltmeters. 901 61 513. 1 : 6. 61 520. 1 : 6. 61 521. 1 : 6. 61 521 and 61 522. 1 : 6. Ammeters and Voltmeters. Demonstration Instruments. 61.520. Direct Current Demonstrating Ammeter, Kohlrausch's system, Figure, range 0.2 — 2 amps., with 20 ampere shunt , 2. 10. 0 The instrument is fitted with a scale visible from a distance and explains the construction of the ammeter in a very comprehensive manner, as all parts are arranged open. The scale can be read from both sides. 61.521. Direct Current Demonstration Voltmeter, Kohlrausch's system, Figure, range 0.5 — 3 volts, with additional resistance for multiplying the range ten times 2. 10. 0 The Voltmeter is the same in construction as Ammeter No. 61,520 and differs from the latter simply in the winding and calibration. Scale can be read from both sides. The current is led into both instruments by the left hand terminals. While in the case of the volt- meter the sensitivity is varied and the range increased by releasing the connection between the right hand terminals, in the case of the ammeter the shunt fitted on the back of the instrument is set into action by inserting the connecting piece between these right-hand terminals. If approximate knowledge of the voltage or current available is not known before hand, this measurement is attempled always with reduced sensitivity, i. e. with resistance in series and with shunt connected. 61.522. Glass Case with brass mount for Nos. 61,520 or 61,521, Figure. Price, each . . 0. 15. 0 Cl. 3344, 5838, 5839, 5840. 902 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. No. 61523 — 61 523 A. 1:6. 61 523 B. 1:6. 61 527. 1 : 5. in. :.L'.{. Dead Beat Universal Moving Coil Measuring Instrument, Deprez-d'Arsonval system, £ * () — 0 — 50 volts, (3) as a Vertical Galvanometer, range 2 — 0 — 2 milliamps. and 200—0—200 millivolts. Can be. read from both sides (see Figs. A and B) r». 1(1. n The instrument is constructed on the Deprez-d'Arsonval system; it has a moving coil in a very powerful magnetic field. Consequently it is independent of its position in regard to the magnetic meridian and of external magnetic influences. The instrument has three pairs of terminals designated respectively "Amp."; "Volts": "Galv.''; the leads are to be connected to these in accordance with the various modes of employment. Two flex i Me cords wit h plugs on the ends are fitted on the moving coil. These plugs are inserted in the ping-holes of the terminals designated "Amp." or "Galv." when it is desired to use the instrument .•i> an Ammeter or a galvanometer. When used as a voltmeter one plug is placed in one of the terminals designated. "Volts", the other being inserted in the plui;- hole of the resistance coil (see l-'ii;. li l..~>2.'! A). (i !..")!' I. -- idem, moving system cannot be withdrawn ft. U. 0 HI. .vjft. Glass Case with brass mount for Nos. ui. :>•>:•> or til. 524 Price, cadi o. i.v o il. 2421,2420, 2432. No. 61 531. Demonstration Instruments. 903 61 528. 1 : 6. 61 531. 1 : 6. 61,526. Additional Voltage Coils for increasing the voltage range of Nos. 61,523 and 61,524 \ £ s. d. in stages of 50 volts each, so that e. g. four extra coils are used for a range of 250 volts Price each 61,527. Universal Measuring Instrument for Direct Current, Deprez-d'Arsonval system, Figure, suitable for current and voltage measurements and for use as a galvanometer The instrument has a scale visible from both sides. The following are the ranges: As a Galvanometer: 0.015 — .0 — 0.015 amp with upprox. 10 ohms resistance. . 2—0—2 and 15—0—15 amps. 3 — 0 — 3 and 50 — 0 — 50 volts. As an Ammeter: As a Voltmeter: r.l.:>i>8. Universal Demonstration Moving Coil Galvanometer with scale visible at a distance, for Direct Current, Deprez-d'AreonvaJ system, Figure, can be used both as a pointer galvanometer for zero methods (resistance measurements and the like) and as a volt- meter and an ammeter. Total height 450 mm, in glass case This instrument has been designed to satisfy the need of an apparatus adaptable for use in as many ways as possible as well as for technical measurements of large current-densities. The graduation is visible at a distance. We have thus five instruments comprised in one, i. e. : (1) Galvanometer. (2) Voltmeter to 3 volts. (3) Voltmeter to 30 volts. (4) Ammeter to 3 amperes. (5) Ammeter to 30 amperes. All leads are laid in the open and can be seen easily at a distance. The connections are changed over by plugs. 61,529. - - idem, considerably larger, total height 60 cm <> 1, 530. Demonstration Moving Coil Voltmeter, for Direct Current, Deprez-d'Arsonval system, cf. Fig. 61,531, with scale visible at a distance; with two ranges, 0 — 3 and 0 — 30 volts, in glass case. Total height 450 mm. Can also be used as a Galvanometer .... This instrument has the same advantages as No. 61,528; change-over by plugs. is 1. .vj l. Demonstration Moving Coil Ammeter for Direct Current, Deprez-d'Arsonval system, Figure, with scale visible at a "distance; with two ranges, 0 — 3 and 0: — 30 amps. In glass case. Total height 450 mm; can also be used as a Galvanometer .... In this instrument, constructed in a similar manner to No. 61,528, change over is effected I iy plugs. 0. 8. 0 5. 0. 0 7. 0. 0 8. 8. 0 6. 0. 0 6. 0. 0 Cl. 6005, 6002. 904 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. No. 61532 — 61534. 1:6. 61 562. 1 : 5. 61 572. 1 : 6. 61 563. 1 : 5. 61565. 1 :/>. 61 570. 1 : «. Electromagnetic Soft Iron Demonstration Ammeters for Direct or Alternating Current, with Air Damping, Fig. 61,534, with moving system (can be taken out), in glass ease: Range For A. C. \ List No. I Price £ 0.2 — 2 61,532 4. 10. 0 1—5 61,533 4. 10. 0 2—10 61,534 4.8.0 2 — 20 61,535 4.8.0 6—30 61,536 4.8.0 6 — 40 amps. 61,537 4.8.0 61,538 4. 12. 0 61,539 4. 12. 0 61,540 4. 10. 0 61,441 4. 10. 0 61,542 4. 10. 0 61,543 4. 10. 0 Electromagnetic Soft Iron Demonstration Voltmeters for Direct or Alternating current, with Air Damping, cf. Fig. 61,534, with moving system (can lie taken out), in glass case. Eange 0.5—3 1—6 For A. C. 2—10 5—25 20— 100 30— 150 40— 200 50— 300 volts 61,546 61,547 61,548 61,549 61,550 61,551 Pri«> £ 4. 15. 0 4. 15. 0 4. 15. 0 4. 15. 0 4. 10. 0 4. 10. 0 4. 15. 0 4. 18. 0 List No. 61,552 61,553 61,554 61,555 61,556 61,557 61,558 61,559 Price £ 4. 18. 0 4. 18. 0 4. 18. 0 4. 18. 0 4. 13. 0 4. 13. 0 4. 18. 0 5. 0. 0 For I List No. 61,544 61,545 D.C.I Apparatus Nos. C>1,532 — <>1. fi.V.I are const ructed as in most electromagnetic instruments, on the principle of the repulsion of two magnetized soft iron pieces of the same name. The frequency should be quoted in the case of A. C. instruments. I'nless tlii.s is stated instruments are supplied calibrated lor 5(1 periods. HI. 560. Reduction in price if the moving system of Nos. 61,532 — 61.55!t is not rei|iiired to be made withdrawable .............................. 0. >•. 61.561. Extra price for subdividing the series resistance for Voltmeters Nos. <;!.."> 1 1 — ill. .V.'.i for obtaining a second range of higher sensitivity. The two ranges must he as I : 2 d. is. n • ; 1.562. Demonstration Instrument after Scotti, for explaining the principle of hot wire in- struments. Figure, on stand, for projection. NEW! ............. 1- Id. <• Cl. 241!), M35, 2428, •-M •.'.'.. '.M'-'li, lM-.'7. Nil. lil 573. Demonstration Instruments. 905 61 573. 61 574. 61 575. 61.563. Demonstration Hot Wire Ammeter after Grimsehl (Ztschr. f. d. phys. u. chem. U. 16, £ s- u- 1903, p. 282 ; Grimsehl, p. 764), Figure; can be used for Direct and Alternating Current; with shunts , 1. 8. 0 The instrument possesses a degree scale and a calibrating scale for the permissible currents up to 1 ampere. By using the shunts the range can be increased to 10 times that of the calibrated scale. The pointer can be bent back so as to use either one or other of the scales. 61.564. Dead Beat Demonstration Hot Wire Ammeter, of. P i g. 61,565, for Direct and Alter- nating Current of from 0 — 5 amperes, in glass case 5. 5. () 61.565. - - idem, with 2 ranges, F i g u r e, for 0 — 5 and 0 — 25 amperes 6. 15. 0 61.566. - - idem, with 3 ranges, for 0 — 5, 0 — 25 and 0 — 50 amperes 7. 10. 0 61.567. Dead Beat Demonstration Hot Wire Voltmeter for Direct and Alternating Current, of. Fig. 61,565, for 0 — 15 volts, with fuses, in glass case 5. 15. 0 61.568. -- idem, with 2 ranges, for 0 — 30 and 0 — 150 volts 6. 15. 0 61.569. -- idem, with 3 ranges, for 0 — 30, 0 — 60 and 0 — 150 volts 7.10.0 (i 1,570. Electrostatic Demonstration Voltmeter for Direct and Alternating Current, F i g u re, for 0 — 1000 volts, with damping magnet 9. 0. 0 61,571. - idem, for 0—500 volts 9. 0. 0 (i 1,572. Demonstration Wattmeter for Direct and Alternating Current, F i g u r e, for 10 amps. and 125 volts, with damping 8. 0. 0 If desired, and at a proportionate variation in price, the wattmeters can be supplied for other current maxima between 0 and 50 amps, and for other voltages. 61, 573. Demonstration Ammeter, Hummel-Schuckert system, Figure, from 0 — 1.3 amps., for projection 3. 15. 0 til, 571. Demonstration Ammeter, Dobrovolski system, Figure, from 0 to 10 amps., for projection 3. 15. 0 61,575. Demonstration Galvanometer, Deprez-d'Arsonval system, Figure, graduated from 0 — 30 milliarnperes, for projection 5. 10. 0 This instrument can also be supplied graduated as a volt- or ammeter. Technical Measuring Instruments. Precision instruments constructed on the Depree-d'Ajsonval system can be recommended before all others for Direct Current, as they are most accurate, dead-beat and possess an even gra- duation commencing from zero. The electromagnetic instruments for direct or alternating current have an air damping arrangement which is efficient in its action. Their finer graduation commences at about ' ' 5 of the maximum deflection. When ordering it should be precisely stated whether these instruments are intended for Direct or Alternating Current. In addition, the periodicity should be given, otherwise instruments for 50 cycles are supplied. For accurate measurements on Alternating Current it is advisable to use Hot Wire Instruments and Dynamometrical Instruments. In these instruments also the finer graduation commences at about V5 of the total deflection. The round pattern instruments are, unless otherwise stated, sup- plied for front connection. 906 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. No. 61576 — 61 583. 1 : 2. 61 605. 1 : 3. Round Pattern Instruments for permanently fixing on switchboards or stands. Ranfjr Electromagnetic Soft Iron Instruments with air damping, for Direct or Alternating Current. Dead Beat Precision Instruments, Dcprez-d'Arsonval, for Direct Current only. Baseplate diameter 125 mm Baseplate diameter 200 mm Baseplate diameter 125 mm Baseplate diameter 200 mm List No. £ s. d. List No. £ s. d. List No. £ s. d. List No. £ >. d. Voltmeters : 3 Volts 61 576 1. 1. 0 61597 1. 8. 0 61626 1. 19. 0 61646 2. 3. 0 5 i, 61577 1. 1. 0 61598 1. 8. 0 61627 1. 19. 0 61647 2. 3. 0 10 „ 61 578 1. 1. 0 61599 1. 8. 0 61628 1. 19. 0 61648 2. 3. 0 15 „ 61 579 1. 1. 0 61600 1. 8. 0 61629 1. 19. 0 61649 2. 3. 0 25 „ 61 580 1. 1. 0 61601 1. 8. 0 61630 1. 19. 0 61650 2. 3. 0 50 „ 61 581 1. 1. 0 61602 1. 8. 0 61631 2. 1. 0 61651 2. 3. 0 75 „ 61582 1. 1. 0 61603 1. 8. 0 61632 2. 1. 0 61652 2. 3. 0 125 „ 61 583 1. 3. 0 61604 1. 9. 0 61633 2. 3. 0 61653 2. 3. 0 180 „ 61584 1. 6. 0 61605 1. 10. 0 61634 2. 3. 0 61654 2. 3. 0 250 „ 61 585 1. 6. 0 61606 1. 11. 0 61635 2. 6. 0 61655 2. 8. 0 300 „ 61607 1. 13. 0 — — 61656 2. 14. 0 400 „ — 61608 1. 16. 0 — — 61657 3. 0. 0 600 „ — 61609 2. 2. 0 — — 61658 3. 6. 0 750 „ — — 61610 2. 7. 0 — — • 1 61659 3. 12. 0 Ammeters : 61 660 2. 3. 0 61 661 2. 3. 0 61 662 2. 3. 0 61 663 2. 3. 0 61 664 2. 3. 0 61665 2. 3. 0 61 666 2. 3. 0 61 667 2. 3. 0 61 668 2. 3. 0 61 669 2. 3. 0 61 670 2. 3. 0 61 671 2. 4. 0 61 672 2. 8. 0 61 673 2. 9. 0 61 674 2. 10. 0 The Precision Amiiictcis having ranges over ."in amperes arc supplied with external shunt. 0,5 Amp. 61 586 0. 19. 0 61611 1. 8. 0 — — 1 „ 61587 0. 19. 0 61612 1. 8. 0 61636 1. 19. 0 3 Amps. 61588 0. 19. 0 61613 1. 8. 0 61637 1. 19. 0 5 „ 61589 0. 19. 0 61614 1. 8. 0 61638 1. 19. 0 10 „ 61590 0. 19. 0 61615 1. 8. 0 61639 2. 0. 0 15 „ 61591 0. 19. 0 61616 1. 8. 0 61640 2. 0. 0 20 „ 61592 0. 19. 0 61617 1. 8. 0 61641 2. 0. 0 25 „ 61593 0. 19. 0 61618 1. 8. 0 61642 2. 2. 0 30 „ 61594 0. 19. 0 61619 1. 8. 0 61643 2. 2. 0 50 „ 61595 1. 0. 0 61620 1. 9. 0 61644 2. 4. 0 80 „ 61596 1. 1. 0 61621 1. 9. 0 — — 100 „ — — 61622 1. 10. 0 — — 150 „ 61623 1 10. 0 — — 200 „ 61624 1. 12. 0 — — 250 „ — 61625 1. 14. 0 — — Kindly read carefully the Preliminary Remarks on p. 905. CI. 44 r. 46 >. No. 61 704. Technical Voltmeters and Ammeters. 907 61 644. 1 : 2. 61 655. 1 : 3. 61 700. 1 : 3. '*'*««, ^^^^^^_ 61 704 and 61 628. 1 : 3. 61.675. Extra Price for the 200 mm diameter Voltmeters, with a third terminal for sub- | £ s. d. dividing the series resistance and obtaining a second range I 0. 12. 0 61.676. Extra Price for the Electromagnetic Instruments if fitted with a spiral spring for enabling them to read correctly in any position Dead Beat Hot Wire . Measuring Instruments for Direct and Alternating Current, 0. 2. 0 Figure, round pattern, independent of magnetic influences (and, in the case of Alternating Current, independent of the current curve and periodicity as well); Base plate 246 mm diameter. Ammeters: Voltmeters : List No. Amperes £ s. d. List No. Amperes £ s. d. List No. Volts £ s. d. List No. Volts £ s. d. 61677 61678 61679 61680 61681 61682 0.5 1 5 10 20 25 3. 15. 0 3. 15. 0 3. 15. 0 3. 15. 0 3. 15. 0 3. 15. 0 61683 61684 61685 61686 61687 61688 61689 50 80 100 150 200 300 500 3. 15. 0 3. 15. 0 3. 15. 0 4. 0.0 4. 0.0 4. 10. 0 5. 0.0 61690 61691 61692 61693 61694 61695 3 6 10 25 40 60 3. 5.0 3. 5.0 3. 5.0 3. 5.0 3. 5.0 3. 5. 0 61696 61697 61698 61699 61700 61701 61702 75 100 125 180 250 300 600 3. 5.0 3. 5.0 3. 5.0 3. 5.0 3. 10. 0 3. 15. 0 5. 0.0 The Ammeters to 50 amps, have the shunt built into the instrument, those over 50 amps, being provided with external shunt. Iron Base for Instruments Nos. 61,576 — 61,674, List No. 61,703 For instruments of 200 £ 0. 6. 0 Figure, for placing on the table. 61,704 125 mm diameter Base plate 0.5.0 Ci. 43 F 52 f 45 f, 2440. 908 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. N.I 01 705 — 61706. 1:8. 61 717 and 61 725. 1 : 5. 61 731. 1 : 4. Wood Stand for Instruments Nos. 61,576 — 61,702, for placing on a table, Figure. List No. 61,705 61,706 61,707 For instruments of 246 200 125 mm diameter Base plate £ 0.12.0 0.10.0 0.8.0 Precision Milliammeters, Deprez-d'Arsonval system, Figure. Range Milliamperes List No. Diameter of base £ s. d. List No. Diameter of base £ s. d. 1—0—1 — — 61715 125 mm 2. 10. 0 5_0_5 61708 80 mm 1. 12. 0 61716 125 „ 2. 5. 0 10—0—10 61709 80 „ 1. 12. 0 61 717 125 „ 2. 5. 0 25—0—25 61 710 80 „ 1. 12. 0 61 718 125 „ 2. 5, 0 50—0—50 61 711 80 „ 1. 10. 0 61 719 125 „ 2. 2. 0 100—0—100 61 712 80 „ 1. 10. 0 61 720 125 „ 2. 2. 0 500—0—500 61 713 80 „ 1. 10. 0 61 721 125 „ 2. 0. 0 1000—0—1000 61714 80 „ 1. 10. 0 61 722 125 „ 2. 0. 0 61.723. Extra Price for a second range for Instruments of 80 mm and 125 mm diameter £ of base 0. 7. (» 61.724. Extra Price for three ranges — only applicable to instruments of 125 mm diameter of base ..'... 0. 11. 0 61.725. Serpentine Stone Slab with carrying pillars, Figure, for Milliammeteis Xos. 61,708 to 61,722 0. in. o Portable Instruments in Wood Cases. Simple Electromagnetic Soft Iron Instruments with air damping, for Direct or Alternating Current, with lancet shape, pointer, Figure. f Range 5 10 30 75 125 180 250 volts Voltmeters List No. 61,726 61,727 61,728 61,729 61,730 61,731 61,732 I Price £ 1. 11. 0 1. 11. 0 1. 11. 0 1. 11. 0 1. 11. 0 1. 13. 0 1. 14. 0 2 5 10 15 20 40 60 80 100 amps. , List No. 61,733 61,734 61,735 61,736 61,737 61,738 61,739 61,740 61,741 I Price i 1. 10.0 1. 10. 0 1. 10. 0 1. 10. 0 1. 10. 0 1. 10. 0 1. 11. 0 1. 11. 0 1. 11. 0 In the ease of Alternating Current! kindly suite frequency; otherwise instruments for .~>O periods arc supplied. 61,742. Extra Price for two scales for Direct and Alternating Current 0. 3. 8 Dead Beat Precision Instruments, Deprc/-d'Arsonval system, for Direct Current only, with lancet shaped pointer. Figure. I Range Am- v.u 1 Kange 12.5 75 125 250 12.5 and 125 125 anil •_'."><) volts List No. 61,743 61,744 61,745 61,746 61,747 61,748 meters i >,.;..,. »• 9 19 n - .-. -L.-. v 2. 12. 0 2. 14. 0 2. 16. C 1 3. 8. 0 3. 8. 0 I Range 1.5 15 :; meters \ Price £ 4 5 0 4 5 ( Eange 1.5 List' No. 61,761 meters \ Pl.k,e £ 4 5 Q Dead Beat Precision Instruments, Deprez-d'Arsonval system, for Direct Current only, with £ 8 d- knife-edge pointer and mirror scale, Figure. 75 125 250 12.5 and 125 125 and 250 volts 61,756 61,757 61,758 61,759 61,760 4.6.0 4.10.0 5.2.0 5.2.0 15 30 50 75 100 amps. 61,762 61,763 61,764 61,765 61,766 4.5.0 4.8.0 4.8.0 4.10.0 4.12.0 Instruments with different ranges, also Ammeters with external shunt, quoted for on application. Compare also Universal Galvanometer No. 61,362, p. 885. Series Resistances for Precision Voltmeters, Figure, for increasing the range. Maximum Range 15 75 150 200 250 300 600 750 volts List NO. 61,767 61,768 61,769 61,770 61,771 61,772 61,773 61,774 Price £ 1. 2. 0 1. 2. 0 1. 6. 0 1. 8. 0 1. 8. 0 1. 10. 0 1. 18. 0 2. 10. 0 Each Series Resistance can be divided up into as many as five ranges. 61,775. Extra Price for each subdivision 0. 9. 0 61.776. Dead Beat Precision Voltmeter, Deprez-d'Arsonval system, for Direct Current only, Figure, can also be used for measuring insulations with the working voltage; with three ranges, 0—120, 0—240 and 0 — 480 Volts i 2. 6. 0 61.777. Dead Beat Precision Volt- and Ammeter, Deprez-d'Arsonval system, for Direct Current : only, Figure, with six ranges, 0.15, 1.5 and 15 Amps.; 3, 15 and 150 volts . . . 12. 10. 0 Shunts, of Manganin, for above, with leads. Range 30 75 150 amperes List No. 61,778 61,779 61,780 Price £ 2. 0. 0 3. 0. 0 3. 6. 0 Precision Hot Wire Voltmeters for Alternating and Direct Current, Figure. Range 5 :W 75 125 250 6 and 120 125 and 250 volts List Xo. 61,781 61,782 61,783 61,784 61,785 61,786 61,787 Price £ 5. 6. 0 5. 6. 0 5. 12. 0 5. 12. 0 6. 0. 0 6. 6. 0 6. 10. 0 <•]. 40', 41 K, 56 "•', 5524, 39"", 38 r. 910 Voltaic Electricity. Section 3: Electro-Magnetic Current Measurements. No. 61789- 61800. 61 810. 61,789. Precision Hot Wire Ammeter for Alternating and Direct Current, with external shunts (Millivoltmeter), these shunts not being included in the price, cf. Fig. 61,784 . Shunts for above. Eange 10 20 40 60 100 150 List No. 61,790 61,791 61,792 61,793 61,794 61,795 Price £ 0. 10. 0 0. 10. 0 0. 10. 0 0. 12. 0 0. 14. 0 0. 16. 0 200 amperes 61,796 1.2.0 £ s. d. 5. 6. 0 Precision Instruments constructed on the dynamometrical principle, for Alternating and Direct Current, Figures. The graduation on the Voltmeters and Ammeters commences at one-fifth of the maximum scale value. The instruments are provided with leather carrying cases and currying boxes respectively. Voltmeters : List No. Range. Volts max. One Scale-division. Volts Price I II III IV 1 I II III IV £ s. d. With 2 Banges 61797 7.5 15 — I! 0.05 0.1 — — 12. 15. 0 61798 15 30 0.10 0.2 — — 12. 15. 0 With 3 Eanges 61799 7.5 15 30 — 0.05 0.1 0.2 13. 15. 0 61800 15 30 75 — 0.10 0.2 0.5 13. 15. 0 With 4 Eanges 61801 7.5 15 30 75 0.05 0.1 0.2 0.5 14. 5. 0 61802 15 30 75 150 0.10 0.2 0.5 1.0 14. 10. 0 With 2 Eanges 61803 7."> 160 — 0.5 -| — — 13. 0. 0 61804 150 300 — 1.0 2 13. 15. 0 61805 150 750 — 1.0 5 — — 14. 5. 0 61806 300 750 — 2.0 5 — — 14. 5. 0 With :; Killers 61807 7") i;,o :;mt — 0.6 1 2 15. 0. 0 61808 150 :;IMI T:,O l.i) •2 5 16. 0. 0 61809 Witli I 150 u.r. 17. 5. 0 Cl. «7', COP. No. 61 836. Voltaic Electricity. Section 4: Ohm's, KirchhoH's and Joule's Laws. 911 108 OHM ' SILBER KUPFER UStN NEUSIIBER COHSTANSTAN 61 833. 1 : 8. 61835. 1:11. Ammeters : List No. Ranges. Amperes maximum One Scale-division. Amps. Price £ 8. d. | I | • II I II 61810 61811 61812 61813 61814 61815 I 5 1 2.5 5 10 With 1 Range 0.01 0.05 With 2 Eanges 2 0.01 5 0.025 10 0.05 20 0.1 0.02 0.05 0.1 0.2 10. 10. 0 10. 10. 0 12. 5. 0 12. 5. 0 12. 5. 0 12. 5. 0 60,118. Precision Compass for determining the direction of current in leads and the poles £ »• d. in magnetic fields, Fig. 60,118, p. 792 0. 12. 0 The instrument is closed on both sides by watch glasses in order to render the magnet needle always visible. The magnet needle itself is very light, thoroughly well balanced, and rests in stones. As the in- strument always gives a plain deflection when brought into the immediate neighbourhood of a conductor traversed by a current of 0.1 ampere, it is consequently possible to ascertain the direction of flow of currents in conductors. Section 4: Ohm's, Kirch hoff's and Joule's Laws. 3. Apparatus for Fundamental Resistance Experiments, Figure, comprising 5 wires £ »• of 1 m length stretched between clamps on a polished board. The resistance of each wire can be measured singly. The wires are: 3 Manganin wires of 2, 1 and 0.5 mm; 1 Iron wire of 0.5 nun and 1 Silver wire of 0.5 mm diameter U1.X34. -- idem, after Weinhold (W. D., p. 782 [723]), on board with terminals 1. 0. 0 1. 0. 0 <>l,x.;r>. 5 Wires of Constantan, German Silver, Iron, Copper and Silver, Figure, of same thickness and same resistance, the lengths corresponding to the specific resistance; on hoard with pole terminals 1. 0. 0 61,836. 4 Wires of Copper, Brass, Iron and Manganin, of same length and same cross section. in glass vessel for filling with paraffin, for determining specific resistance (M. T. Fig. 198) 1. 4. 0 01. •-'•(. 18, 2459. 912 Voltaic Electricity. Section 4: Ohm's, Kirchhoff's and Joule's Laws. No. 61837 - 61 839. 1 : 9. 61843. I: 10. 61 837. 1 : 5. 61 841. 1 : 0. . „„..»... .».Mt •*«...«.. 61 843. 1 : 4. 61 846. 1 : 6. 61.837. Rheostat after Whcatstone (M. P., 10'h Edn., IV, 1, Figs. 343 a and b; 9th Edn., Ill, Pigs. 361 and 362), Figu re, with 1 slate cylinder 160 mm long. The resist mice corresponding to one turn should be quoted 61.838. - - i d e m, with 1 cylinder 250 mm long 61.839. Rheochord after Poggendorff, Figu r e (M. P., 9th Edn., Ill, Fig. 364), with 2 pla- t ilium wires 1 m long and mercury contact vessel 61.840. Rheochord, Figure, simple, with sliding contact, measuring wire 500 nun long 61.841. 4 Resistance Spirals of thick Manganin Wire, F i g n re. after Friedr. C. G. Miiller (M. T. Fig. 194) one. each of 1, 0.5, 0.2 and 0.1 ohm 61.842. Resistance of 0.01 ohm, for Shunt Experiments, after Friedr. ('. G. Miiller (M. T. Fig. 1!»5) 61.843. 3 Resistance Spirals, after I-Yiedr. C. G. Miiller, Figure (M. T. Fig. 191), of copper, German silver and manganin, of equal length and cross section, for demonstrating temperature coefficient 61.844. Device for explaining that the conducting resistance of a metallic conductor depends upon the temperature; with platinum wire (\Y. I). Fig. 514 [487J) 61.845. Device for the same Purpose, for liquids (W. D. Fig. 515 [488]) (•]. 24 II-.'. 21110, 4 133, 4809, £ s. il. 3. 0. 0 3. 6. 0 4. 0. 0 ' 1. 10. 0 0. 16. 0 1. 0. 0 0. 0. 0 n. 4. 0 0. 1.0 24(53, 2474. No. til 87'.'. Resistances. 913 61 848, 61 849. 1 : 4. 61 854. 1 : 4. 61 871. 1 : 20. 61847. 1:8. 61 872. 1 = 10. 61,846. Apparatus for showing the Influence of Temperature on Resistance, Figure £ s. d. (W. u. E., Fig. 301), with one spiral each of platinum, nickelin, iron and copper on wood reels in two reagent flasks, with heating vessel, stirrer and thermometer . . 2. 0. 0 (> 1,847. Apparatus for the same purposes, after Grimsehl, Figure, with iron wire and manganin spiral heated by a Bunsen burner. A small glow lamp serves as indicator (Grimsehl, Fig. 819) . . ' ' 61,849. Siemens Unit, of manganin, bifilar wound, Figure, adjusted at 20°C., in metal case, arranged to receive petroleum for maintaining a constant temperature ' . . We still supply this unit as being of historica interest. Single Resistances for forming sets, Figure, of constantan, in metal case, bifilar wound, calibrated at 20° 0., with connecting links for forming complete sets of resistances; also suitable for scholars' exercises. The terminals have double nuts so as to be able conveniently to introduce branches. List No. 61,850 61,851 61,852 61,853 61,854 61,855 61,856 61,856 a 61,857 61,858 61,859 Resistance 0.1 0.2 0.3 0.4 1 2 3 4 10 20 30 ohms £ 0. 3. 0 0. 3. 0 0. 3. 0 0. 3. 0 0. 3. 0 0. 3. 0 0. 3. 0 0. 3. 0 0. 3. 0 0. 3. 0 0. 3. 0 List No. 61,860 61,861 61,862 61,863 61,864 61,865 61,866 61,867 61,868 61,869 Resistance 40 100 200 300 400 1000 2000 3000 4000 10,000 ohms £ 0. 3. 0 0. 4. 0 0. 4. 0 0. 4. 0 0. 4. 0 0. 4. 0 0. 4. 0 0. 4. 0 0. 4. 0 0. 5. 0 61,s7(». 3 Resistance Coils each of 100 ohms, on wood board (W. D. Fig. 516 [489]) . . 61,871. Conductor after Kolbe, Figure (Kollie - Skellon, Introduction to Electricity, Part I, Fig. 3) <> 1.872. Rheostat after Kolbe, for demonstrating relative resistance, Figure (Ztschr. f. d. phys. u. chem. U. 20, 1907, p. 82); can also be used as a bridge and for students' exercises A baseboard (which is also arranged for hanging on the wall) has four wires of constantan, iron, brass and copper of the same cross section, the three first named being provided with a sliding contact. The constantan wire is provided with double push terminals and scale for use, thus enabling it to be used also as a bridge wire. 0.11.0 61,848. 1 Ohm for School Use, of manganin, bifilar wound, Figure, adjusted at 20° C., in metal case arranged to receive petroleum for maintaining a constant temperature j 0. 16. 0 0. 16. 0 0. 16. 0 1. 5. 0 5. 0. 0 Cl. 2464, 5518, 5730, 5971,5216. 58 914 Voltaic Electricity. Section 4: Ohm's, Kirchhofi's and Joule's Laws. No. 61873 — 6 1 873 A. Fi-ont View. 1:8. 61 873 B. Back View. 1 : 8. 61,873. School Rheostat after Kolbe, Figs. A and B (Ztschr. f. d. phys. u. chem. U. 21, t »• <'• 1908, p. 217), with supplementary rheostat and table of resistances on the back . 7. 0. 0 Fig. A shows the front of the apparatus. Upon a white lacquered, vertical wood slab is arranged ; first of all a single ohm of bare constantan wire, which can be regulated between 0 and 1 ohm without intermediate steps, by means of a reliable sliding contact. The resistance values corresponding can be read off on an easily interchangeable cardboard scale. This cardboard scale is interchangeable in order that it can be arranged properly when the constantan wire has undergone some wear. To the right of the single ohm is a switch handle rheostat of constantan wire, consisting of 20 spirals of 0.5 ohm each, covered green, and two spirals of red-covered manganin wire (visible on the back) of 5 ohms each. All spirals can be got at easily by the employment of push terminals and can easily be re-calibrated should this prove necessary after long use. All connections are laid open, being comprehensively arranged. The single ohm and the switch handle rheostat are connected in series but can also be used independently. All values between 0 and 21 ohms can be got in fine stages by means of two handles. On the back of the rheostat (Fig. B) is fixed a table containing the resistances of the commoner metals together with the resistance per metre and the length per ohm for wires of one mm diameter, also the relative resistances. In addition there is also a supplementary rheostat consisting of >/i metre of 0.3 mm thick platinum, iron, brass, and copper wire and 1 m each constantan wire 0.3 and 0.6 mm thick and man- ganin wire 0.3 and 0.9 mm thick. All these wires are accessible singly. All numbers are painted on very distinctly and are visible at a distance. in. XT 1. - • idem, without supplementary resistance and without table of resistances on the back 6. 0. o 61,875. Demonstration Sliding and Plug Rheostat, after Krlemann, Figs. A, B and (.' (Ztschr. f. d. phys. u. chem. U. 22, 1909, p. 353) 12. 0.0 The rheostat consists of two upright boards joined together by a hinge and a single board for the single ohm, it being possible to attach this smaller board to the large one. Fig. A shows the front with the single ohm 0 — 1 ohm attached, plug resistance 0 — 210 ohms, and sliding resistance o — In ohms. A copper, iron and Herman silver wire of equal length and equal cross section are stretched zig-zag fashion across the back (Fig. B). In addition the back contains s \\ire- of :>(> cm length (3 each of cross Section 1. 2 of cross section -J. ami :; of cross section 3). Fig. C shows the front folded up with the single ohm taken off and fixed on a special baseboard. This rheostat can be used in a great variety of ways and the zig-zag arrangement of the resistances assists the comprehension of the students. f.l.XTti. - - idem, with back blank 10.10.0 M. 5179,5180. No. C1881. School Rheostats. 915 61 875 A. 1:10. 61 875 C. l:ld. 61 880. 1 : <>. £ s. (1. <>1.X77. Single Ohm, alone, cf. Fig. 61,875 C, to the right 1.10.0 l,ssi. Slide Wire Resistance alone ... l- r>. o Cl. 5369, 537 1 , 5370, 2472, 3937. 58* 916 Voltaic Electricity. Section 4: Ohm's, Kirchhoff's and Joule's Laws. N... r.l 883 61 888. 1 : 5. 61 892. 1 : 10. 61893. 1:13. 61.882. Switch Contact Rheostat, Figure, in wood case with ebonite top, with 22 stages, 0, 1, 2, 4, 6, 8, 10, 15, 20, 30, 40, 50, 60, 75, 100, 150, 200, 300, 400, 500, 750, and 1000 ohms (total resistance) ....................... 61.883. --idem, in 22 stages, total 2000 ohms .................. 61.884. - - idem, in 22 stages, total 3000 ohms .................. 61.885. -- idem, in 22 stages, total 4000 ohms .................. 5. 61.886. — idem, in 27 stages, 0, 1, 2, 4, 6, 8, 10, 15, 20, 30, 40, 50, 60, 75, 100. 150. L'OO, 300, 400, 500, 750, 1000, 1500, 2000, 3000, 4000, 5(100 ohms (total resistance) The maximum load for Rheostats Nos. 61,882 — 61,886 is, for the units. o,:t ampere: for the tens. o. I ampere: for the hundreds, 0.05 ampere; and for the thousands. n.O-J ampere. The resistances are only approximately correct . .."> ohm. The drum is rotary and thus more or less resistance can lie put in. <>M a hoard are titled four coils with ."). lo. l.~> and '2<> ohm and a rheochord with 0.1 ohm resistance. Total resistance. .~>o ohms. The apparatus is v«ry compact, and the scale visihle at a distance. 61,115. Forceps for Shunting, for above, Figure on p. * 61.894. - - idem, with Resistances which can be put in parallel or series, Figure, with a precision ammeter for the main circuit, 4 small ammeters, 3 change-over switches, and 1 switches, also a precision voltmeter with plug cords 61.895. Apparatus for explaining the Wheatstone Bridge hydrodynamically, after Noack, Figure (Ztschr. f. d. phys. u. chem. U. 1, p. 236), with Current Indicator after Szymanski (Ztschr. f. d. phys. u. chem. U. 2, p. 272) £ s. d. 1. 15.0 2. 0.0 2. 15. 0 7.10.0 18. 0.0 24. 0. 0 4. 0.0 Cl. 4124,5881. 918 Voltaic Electricity. Section 4: Ohm's, Kirchhorf's and Joule's Laws. N... Ill 896 61897. 1 : 61 896. 1 : 9. 61 898. 1 : 12. MAX KOHL, CHEMNITZ. 61899. 1 : 10. 61 900. 1 : 8. 61 901. 1 : 3. 61.896. Apparatus for explaining the Wheatstone Bridge, after Spies, Figure, with t 4 glow lamp brunches (Ztschr. f. d. phys. u. chem. ['. 12, p. 78) . l'. 8. The glow lamps can be switched out singly and resistances connected to the terminals pertaining to the lamps for comparison purposes. 01.897. School Pattern Wheatstone Bridge a fter Kolbe, Figure, for demonstration and students' exercises (Ztschr. f. d. phys. u. chem. I'. 20, 1907, p. 78) . I. Hi. o In constructing this apparatus the value, has been emphasized of comprehensiveness, plain figuring visible at a distance, and ease of manipulation. The connections have been made on the principle of Kohl- rausch's bridge. The measuring wire with its slider (',.,, ,'i comparison resistances of U.I, 1 and Id ohms. a reversing switch G,, 1 key, also the terminals, are mounted on one baseboard. The slider of the pilot wire slides over two different scales, one of these being provided with a graduation in hundred! hs, the other — the scale used — being divided according to the quotient . The bridge can also be hung Jdd a upon the wall. »Ji.x98. Wheatstone Bridge for teaching purposes, Figure, with stretched measuring wire, 1 ni long, of constantan, divided in half-decimetres for the audience, and in millimetres .for the teacher; without comparison resistances 1. Hi. d 61,8»9. 4 Comparison Resistances for above, of o.l, 1. r> and f> ohms, Figure .... i'. u. it The comparison resistances are prepared of manganiii, the temperature coefficient of which is negli- gible. The wires are stretched in the open and are non-inductive; and the individual amounts can lie easily put in circuit by drawing out the corresponding plug. Very neat and convenient to manipulate til ,9d(). 3 Comparison Resistances for No. 61,898, of o.l, 1 and 10 ohms. Figure . . 1. Id. o The smallest resistance of 0.1 ohm is of copper: the other two resistances of 1 and 10 ohms respec- tively being made of constantan wire, so that it is possible to show the ratio of the specific resistances. The exact resistance values are given on the upper edge of the board. til, 901. 4 Simple Comparison Resistances, Figu re, of manganin, wound on wood reels; 0.1, 1, 5 and 5 ohms | 1. 0. 0 Cl. 2489, .1234, MM, -.'ttlii. .YS'.til -.>467. No. 61913. Simple Wheatstone Bridges. Standard Resistances. 919 61 902. 1 : 10. 61905. 1:8. 61 906 — 61 911. 1 : 4. 61 912. 1 : 4. 61.902. Simple Wheatstone Slide Wire Bridge for students' use, after Halm, Figure (Hahn, £ * . 0. 0 U. lii-i'.l, Iti'.MP. I'.ITI. 3892. 41USI. No. 01832. Standard Resistance. Petroleum Baths. 921 61 932 A. 1:8. 61 932 B. 1:3. one massive binding screw for leading in the current and each a second for the potential lead. In the case of the resistances with special shunt terminals the potential lead is fixed to these. The petroleum bath contains a cooling vessel for water circulation and an efficient turbine for circulating the petroleum. The turbine lias a cord drive, being actuated by a small electric motor or a water motor. 61,928. Petroleum Bath for 4 Eesistances, with one turbine, 5 short bars with terminals and mercury cups for series connection and 2 long bars for parallel connection of the re- sistances, Figure £ s. d. 61.929. - - i d e in, without the two paralleling rails 61.930. - - i d e in, for 5 resistances, with turbine, 6 short and 2 long copper bars 61.931. - - i d e in, without the 2 copper paralleling bars 7. 0.0 6. 0.0 9. 0.0 7. 15. 0 61,932. Petroleum Bath, Figs. A and B, own new pattern, for comparing single resistances and two resistances in series and for determining temperature coefficients; with heating and cooling arrangements, Fig. B ; can also be used as it stands for the Thomson method of connecting Standard Resistances can be compared both by the Wheatstone and the Thomson method with t lie aid of the shunting resistances Xos. 61,924 — 61,926. The heating is done by a glow lamp and the cooling by a water jacket and stirring turbine. Resistances and Bridges for Scientific and Technical Purposes. Precision Rheostats of Manganin Wire, impregnated with shellac and heated for 10 hours to 140° C. before calibration. The ends of the resistance coils are silver soldered flush on to copper pieces and the latter can be soldered with tin to the bolts which are used us conductors. The plugs have ebonite grips. The plug blocks are provided with special plug-holes for in selling wire connected terminals so as to be able to use each resistance coil singly. The resistance coils to 5 ohms are wound bifilar (non-inductive), those above 5 ohms in accordance with Chapron's method (non-inductive and anti-capacity). Each resistance box has openings which may be closed, for steadying the temperature, and opening for taking a thermo- meter. The error of calibration of the precision resistances is within one part in one thousand. The resistances are calibrated in International Ohms. The following is the permissible load : Resistance in Ohms 0.1 — 0.4 1 — 4 Permissible Current, Amps. 1 0.4 100—400 0.04 1000—4000 0.015 10 000—40 000 0.003 16. 0. 0 Cl. 4968, 4972. 922 Voltaic Electricity. Section 4: Ohm's, KirchhoH's and Joule's Laws. X<>. «l 933 — 61 948. 1 = 8. Gl 951. 1 : 8. 61,934. 61,935. 61,936. - 61,937. 61,938. 61,939. 61,940. 61,941. 61,942. 61,943. 61,944. 61,945. 61,946. 61,947. 61,948. 61,949. 61,950. - „ 6 „ 6 „ 6 „ 6 „ 6 „ 8 „ 8 „ 8 „ 8 „ 8 „ 12 „ 12 „ 14 „ 14 „ 18 „ 18 22 Precision Series Rheostats, Figure (cf. Gan.-Man. Fig. 769; Gan.-Eein. Fig. 844). 61,933. - - With 6 Plugs: 0.1; 0.1; 0.2; 0.3; 0.4; 1 Ohm , 1; 1; 2; 3; 4; 10 Ohms , 10; 10; 20; 30; 40; 100 Ohms , 100; 100; 200; 300; 400; 1000 Ohms , 1000; 1000; 2000; 3000; 4000; 10000 Ohms , 10,000; 10,000; 20,000; 30,000; 40,000; 100,000 Ohms .... , 1; 1; 2; 3; 4; 10; 20; 30 Ohms , 1; 2; 3; 4; 10; 20; 30; 40 Ohms , 10; 10; 20; 30; 40; 100; 200; 300 Ohms . , 10; 20; 30; 40; 100; 200; 300; 400 Ohms , 100; 200; 300; 400; 1000; 2000; 3000; 4000 Ohms , 1; 1; 2; 3; 4; 10; 20; 30; 40; 100; 200; 300 Ohms , 0.1; 0,1; 0.2; 0.3; 0.4; 1; 1; 2; 3; 4; 10; 20 Ohms , 1; 1; 2; 3; 4; 10; 20; 30; 40; 100; 200; 300; 400; 1000 Ohms , 0.1; 0.1; 0.2; 0.3; 0.4; 1; 1; 2; 3; 4; 10; 20; 30; 40 Ohms . „ 0.1; 1; 1; 2; 3; 4; 10; 20; 30; 40; 100; 200; 300; 400; 1000; 2000; 3000; 4000 Ohms „ 0.01; 0.1; 0.2; 0.3; 0.4; 1; 1; 2; 3; 4; 10; 20; 30; 40; 100; 200; 300; 400 Ohms • ' „ 0.1; 0.2; 0.3; 0.4; 1; 1; 2; 3; 4; 10; 20; 30; 40; 100; 200; 300; 400; 1000; 2000; 3000; 4000; 10,000 Ohms 61,951. Extra Price for constructing the Rheostats with two glass side walls, Figure, for demonstrating the internal arrangement Precision Decade Resistances of manganin, comprising 10 similar resistances totalled by a plug. List No. 61,952 Resistance 10 x 0.1 £ 7.0.0 The decimal resistances possess the advantage in accurate working that one plug only is always inserted so that the contact resistance is always the same. A second plug is supplied in order thai the circuit may remain uninterrupted. Precision Decade Resistances of manganin, grouped up to a contact handle, Figs. A and B, with covered contacts; the resistance indicated by projecting figures. Fig. B shows the contacts (covers removed). One Decade: List No. Resistance £ Two Decades: List No. I RcsistancelO £ 1 Three Decades: List N<>. 61,971 HcsistancelOxO.l, 1 & 10 £ 15. 10. 0 £ s. d. 5. o. (> 4. 4. 0 4. 8.0 4. 14.0 8. 0.0 11. 0.0 5. 10. 0 5. 10.0 5. 10. 0 5. 10. 0 (i. 10. 0 7. o.it 7. o. o S. (I. 0 8. (I. (I 11. o.o 10. 10.0 13.li>. <» 0. ('. 0 61,953 10x1 6. 10. 0 61,954 10 x 10 6. 10. 0 61,955 61,956 10x100 10x1000 6.10.0 7.10.0 61,957 10x10,000 9.0.0 61,958 10x100,000 ohms 25.00 61,960 10x0. 6.0.0 .,966 0.1 & 1 10.0 61,961 1 10x1 6.0.0 61,967 10x1 &10 10. 10. 0 61,962 10x10 6.0.0 61,968 61,963 10x100 6.0.0 61,964 10 X 1000 7.0.0 61,969 61,965 10x10,000 ohms 9.0.0 61,970 10 XlO & 100 10 x 100 & JOOO 10 X 1000 «.V 10,000 ohms 10. 10. 0 10. 10. 0 10. 15. 0 61,972 10x1, 10 &100 15. 10. 0 61,973 10x10, 100 & 1000 ohms 15. 10. 0 Cl. 5S93, No. 61 996. Precision-Rheostats. Rheostats for Technical Purposes. 923 sis 61 977 A. 61 977 B. 61 996. Four Decades: £ * <*• List No. 61,974 61,975 61,976 Resistance 10 X 0.1,1, 10 & 100 10x1, 10, 100 & 1000 10x10, 100, 1000 & 10,000 ohms £ 20. 10. 0 20. 10. 0 20. 10. 0 77. Five Decades: 10x1, 10, 100, 1000 & 10,000 ohms i>r>. !().(» Technical Decade Resistances, of Manganin, Figure, connected up to switch contacts; adjustment accurate to at least 0.5%. One Decade: List No. 61,979 61,980 61,981 61,982 61,983 61,984 Resistance 10x0.1 10x1 10x10 10x100 10x1000 10 x 10,000 ohms £ 3. 0. 0 3. 0. 0 3. 0. 0 3. 0. 0 3. 10. 0 4. 10. 0 Two Decades: List No. 61,985 61,986 61,987 61,988 61,989 Resistance lOxO.l&l 10x1 & 10 10x10 & 100 10 x 100 & 1000 10 x 1000 & 10,000 ohms £ 5.5.0 5.5.0 5.5.0 5.5.0 5.10.0 Three Decades: List No. 61,990 61.991 61,992 Resistance 10x0.1, 1 & 10 10x1, 10 & 100 10x10, 100 & 1000 ohms £ 7.15.0 7.15.0 7.15.0 Four Decades: List No. 61,993 61,994 61,995 Resistance 10x0.1, 1, 10 & 100 10x1, 10, 100 & 1000 10x10, 100, 1000 & 10,000 ohms £ 10.5.0 10.5.0 10.5. 0 «;i,• with ratio arms: 10; 100; 100; 10; and comparison rheostat: 1; 2; 3; 4; 10; 20; 30; 40; 100; 200; 300; 400 ohms 10. 0. n 62.022. - - idem, with 20 plugs, with the same ratio arms and with comparison rheostat : 0.1; 0.2; 0.3; 0.4; 1; 2; 3; 4; 10; 20; 30; 40; 100; 200; 300; 400 ohms |12. 0.0 »;:.'. 023. Universal Pattern Wheatstone Bridge after Kohlrausch, Figure, with 5 com- parison resistances: 0.1, 1, 10, 100 and 1000 ohms; very practical for rapid measure- ments on wire resistances and electrolytic resistances 7. 10.0 The resistances are read direct (without table) on a scale. In conjunction with a suitable galvano- meter, e. g. No. 61,297 or 61,360, the apparatus serves for resistance measurements of from 0.05 to 20.000 ohms of solid conductors. By using alternating currents, generated by a small induction coil on the appa- ratus, and a telephone instead of the galvanometer, it is possible to determine resistances of electrolytes, the internal resistances of cells, also the contact resistances of earth plates of lightning anvstrrs. tii'.OiM. Box Telephone for above, for determining the resistance of electrolytes, with coil wound to suit 0. l.r>. 0 02.025. Kohlrausch Bridge, without induction coil, otherwise as No. 62,023; range 0.05 to 20,000 ohms; can only be used for wire resistances by employing a suitable galvano- meter, e. g., No. 61,297 or 61,360 '....' G. 0. 0 »»2.o2G. Portable Resistance Testing Set, Figure, comprising Universal Mridge No. 62,023, tialvanometer No. 61,297, Telephone No. 62,024 and 3 Dry Cells, the whole in a solid lock-up oak carrying case, with handle 15. 15. 0 62.027. --idem, but with Galvanometer No. 61,360, which is independent of external magnetic influences and requires no special adjustment 13. .V '_', 033. Potentiometer for measuring potential differences of 0.001 — 190 volts by comparison with a standard cell, Figure. Price without standard cell, but with galvanometer 25. 0. 0 The apparatus contains: a switch contact resistance, 2 slide wire resistances, a pointer galvanometer, a change over switch for the standard cell and the potential difference to be measured, also a galvano- mctcr switch. In addition to measurements of potential the apparatus can, with the aid of standard re- MMaiirrs Nos. 01,914 — 61,923, be used for accurate current measurements. As standard cells, we give the preference to the use of a Weston No. 60,732, p. 845, but a Clark No. 00.731, p. 845, can also be used. Cl. 3528,2505, 5910 », 5909 a. 11. 0.0 928 Voltaic Electricity. Section 4: Ohm's, Kirchhoff's and Joule's Laws. No. 62034 — 62 035. 1 : 5. 62 036 — 62 039. 62 040. 1 : r>. 32,034. Telephone Bridge after Nippoldt, Figure, range from 0.01 to 100 and 0.1 to 1000 ohms, comprising measuring wire, 2 comparison resistances, 1 telephone; can also he used for measurements with galvanometers and by the Wiechert method 62,035. Lightning Arrester Test Apparatus, comprising a Nippoldt Telephone Bridge No. 62.0.51. an extra-current apparatus as generator of alternating currents, and dry cell, in wallnut box, with leather case and carrying strap, Figure Ohmmeter for reading resistances direct, Figure, for connecting up to accumulators, with magnetic shunt to render the readings independent of the working voltage. List No. 62,036 Pressure necessary. Volts 4 ( 0—250 & Hang.-. Ohms | .>-„_.-(,<, t 7. 10. 0 62,037 4 0—500 & 500—1000 7. 10. 0 62,038 12 0—2:100 62,039 20 0—5000 1>500 — 5000 5000 — 10,000 8.0.0 8.5.0 »i2.oio. Induction Apparatus with current-interrupting tuning fork, alter rppcnhorn. Figure, for resistance-determinations of electrolytes in conjunction with a bridge mid a telephone 5.10.0 !l. 0. 0 1. L5. it (1. 2515, 5908", 55 F, 5849. No. 62047. Resistance of Electrolytes. 929 62 042. 1 : 8. inO 62 046. 1 ; c>. »'o. 62,044, with 2 zinc plates (Kolbe-Skellon, Introduction to Electri- city. I 'ait IT, Fig. 124), for use as a current damper and for demonstrating electrolytic resistance I 1. 10. 0 60,747. -- idem, with a zinc and a carbon plate (cf. Fig. 60,747, p. 847) 1.10.0 60,748. -- idem, with partition and a pair of extra plates, Fig. 60,748, p. 847 2. 0.0 62,040. Apparatus for Electrolytic Conduction, after (Irimsehl, for showing that pure water has a very high resistance and that only by the addition of a few drops of sulphuric acid is the current rendered appreciably conductive. Figure 1. 12.0 62,047. Apparatus for determining the Conductivity of Electrolytes, F i g u r e, after Friedr. i C. G. Miiller (M. T. Fig. 199), with one pair electrodes each of iron and of lead. . 0.18.0 Cl. 2517,2479, 5983, 4194. =.n 930 Voltaic Electricity. Section 4: Ohm's, Kirchhoff's and Joule's Laws. No. (V204S — 62048, 62051, 62053, 62054, 61946, 62056, 62057, 62058, 62060. 1:11. 62048. 1 : 11. 1 '"Fnmnrr.nn 62 052. 1 : 8. Apparatus after Prof. Ostwald, for Determining the Conductivity of Electrolytes, Figures £ «• l. Apparatus for Determining Conductivity, after Ostwald, portable pattern, built into £ * l] lock-up wood box, with bridge, precision resistance, 1 — 500 ohms, induction apparatus for producing buzzing sound in sound insulating box, round-shaped telephone with antiphone*, current key, and accumulator 17. 0. 0 The Kohlrausch Bridge No. 62,023, p. 926, is also very well adapted for Determining the Conduc- tivity of Electrolytes. <;•_', oi;2. 3 Resistance Vessels for Electrolytes and 2 Platinised Platinum Electrodes, after Kohl- rausch, Figure (M. P., 10'" Edn., IV., 1, Fig. 479; 9th Edn., Ill, Fig. 406; Gan.- Rein., Fig. 956), with tubes 8, 14 and 25 mm diameter, each vessel having a stand 4. 0. 0 <;2.oi>3. Resistance Vessel for Electrolytes, after Kohlrausch, Figure, with thermometer and graduation on the vessel 1. 10. 0 :.', u<;7. Apparatus for Demonstrating Phototelegraphy, after Kom. roniprisinji 1 table with * »• •'• complete Transmitting Apparatus, lid or i>iio volt I). <'. I>rivinislancc wlicti >lroni;ly illiiiiiiii:ilc2,07o. Diapositives of Tele-photographs (i2,071. Baretter Set after BC'la Gati, for measuring telephone and high frequency currents, built into portable mahogany case T, e Baretters ave fine wires of high temperature coefficient, being heated by the currents to be measured. Their change in resistance, which gives a measure for the current, is measured by the bridge connections of the Baretter set. In this manner it is possible to measure weak alternating currents, e. g. telephone currents, by means of a portable moving coil pointer galvanometer. fii'. 072. Baretters of Platinum or Gold, without vacuum, 0.002 mm diameter quoted for on application. i;2.07.'i. Baretter of thin wire or in evacuated vessel. Price according to sensitivity £ 2. 0. 0 to D2.071. Moving Coil Pointer Galvanometer for above, 1 degree = 0.000,000,1. amp., for maxi- mum sensitivity This instrument requires a perfectly steady base. ti2.i>7r>. Moving Coil Pointer Galvanometer for above, 1° = 0.000,001 amp., sufficient for most purposes, also for use on ships <;2.n7(i. 2 Measuring Accumulators for above, built into wood case Condensers. For Condensers for Electrostatic Measurements, see pp. 833 — 834. \Vc supply two patterns of condensers for galvanic measurements. Our precision condensers are intended for accurate measurements, having as dielectric first-quality mica, the constant being scrupulously determined in our laboratory; their capacity is constant and the insulation excellent. For technical purposes, in which the maximum accuracy is not necessary. \ve can recommend our paraffin-paper condensers, which can stand voltages up to about .'500. The paper condensers are calibrated accurately to within about !<>",, and the exact capacity is stilted on delivery. Precision Condensers with mica dielectric, with one section, Figure. List No, 62,077 62,080 62,081 62,082 Capacity, mfds. 0.01 0.1 o.r> 1 l 4. 0. 0 4. 10. 0 8. 0. 0 10. 0. 0 4. 15. 0 2. 15. 0 0. 1.0 14. 0.0 2. 10. (I 10. 0. (I 10. 2. 0. 0 ;-.. O Cl. 2523. 934 Voltaic Electricity. Section 4: Ohm's, KirchhotTs and Joule's Laws. NIL (i-Ji 62 085. 1 : 5. 62101. 1:8. 62102. I: 12. Precision Condensers with mica dielectric, with more than one section; the sections can be added by pluming, F i g n r e. List No. 62,085 Capacities of Sections, mfds. 0.1; 0.1 Total capacity, mfds. 0.2 £ 6. 0. 0 List No. 62,087 f 0.01; 0.02; 0.03; Capacities of [Sections, mfds. 0.04; OJ ; 0.2; 0.3; 0.4 Total capacity, mfds. 1.1 £ 15. 0. 0 62,086 0.1; 0.1; 0.2; 0.3; d. I 1.1 12. 10. 0 62,088 0.001; 0.002; 0.003; 0.004; 0.01; 0.02; 0.03; 0.0 1; 0.1; 0.2; 0.3; 0.4 1.11 20. 0. 0 Condensers with paraffined paper dielectric, in mahogany box. with one section: List No. 62,090 62,091 62,092 62,093 62,094 62,095 62,096 62,097 Capacity, mfds. o.i £ 2.0.0 0.2 0.6 1 2.5.0 2.10.0 3.10.0 4.10.0 6.0.0 10 20 8. 0. 0 10. 0. 0 - idem, \\illi a number of sections: List No. 62,098 Capacities of Sections, mfds. | ' I o..>; l Total capacity, mfds. 2 £ 6. 0. 0 62,099 I; 2; 2 8.0.0 62,100 1; 2: 2; * ; 20 16. 0. 0 1(1 If de.sired we also supply the paper condensers with I lie stages arranged in any other iniinner desired to suit special circumstances, and shall be jilad to quote prices on application. i-l. •J.-.24, 411'J. l'.i.'». No. 62113. Condensers. Determination of Capacity. 935 62 103 — 62 108. 1 : 9. 62,101. Double Commutator, Figure, after Ayrton and Perry (Elektrot. Ztschr., 1889, p. 412), for measuring capacities and coefficients of self induction and of mutual induction by means of the Wheatstone Bridge; on board with 110 volt D. C. motor, tachometer, regulating resistances for securing wide degree of regulation, stepped pulley, switch, plug contact with plug and 2 metres flexible 16. 0. 0 The measurements can be made with much more certainty with the aid of a mirror galvanometer than with a telephone. <>2,102. - - i (1 e m, built into a table, Figure. On the table are placed the arrangement for measuring insulation resistances as well as various instruments for measuring capa- cities and coefficients of induction » . . :27. 0. 0 In addition to showing the apparatus mentioned under No. 62,101, the Figure illustrates the switch, plug boxes, 6 terminals, 1 motor switch. 1 key (all fitted to ebonite slabs), fixed on to the table-top; these articles are included in above price. Not included in the price are: the Plug Rheostat, the Cells, and the Galvanometer Shunt. The resistance coils of the precision rheostat should be wound so as to be non- inductive and anti-capacity (Chaperon's method). As a suitable Mirror Galvanometer we can recommend '. our Galvanometer No. 61,407, with Reading Device No. 61,409 for fitting to the ceiling. Apparatus for determining Dielectric Constants, chiefly of Liquids, after Nernst (Kohlrausch, Praktisehe Physik, 10lh Edn., p. 575), Figure, comprising: 62.103. String Induction Coil with shunt liquid resistances j 1. 12. 0 62.104. 2 Measuring Condensers with shunt liquids resistances 6. 10. 0 62.105. Testing Condenser for the liquid to be tested 0. 9. 0 62.106. Round Pattern Telephone with antiphone* 0. 9. 0 62.107. Thermometer 0. 3. 0 62.108. Connecting Flexibles 0. 2. 0 Apparatus for determining Dielectric Constants of Solids, for demonstration purposes, after Grimsehl (Ztschr. f. d. phys. u. chem. U. 16, 1903, p. 21), consisting of: 62.109. Condenser with 3 Plates, the centre one being fixed and the two outer ones movable, with arrangement for carrying the plates which are to be inserted and tested ... 2. 5. 0 62,103. String Induction Coil with liquid shunt resistances 1.12.0 62,106. Round Pattern Telephone with antiphone * 0. 9. 0 «2.112. Dry Cell 0. 3.0 In place of No. 62,103 a small electric machine can be used, in which case the shunt resistances are formed of. 62,113. 2 Glow Lamps with Holders, mounted on slate j 0. 6. 0 * See note on p. 930. c| 52.,7 936 Voltaic Electricity. Section 4: Ohm's, Kirchhoff's and Joule's Laws. No. 62116. 1:8. 62 117. 1 : 5 62 115. 1 : 5. 62120. 1:7. Heating Effects of the Electric Current, Joule's Law. ti-.lll. Apparatus for showing the Generation of Heat by the Electric Current, F i «• u re (M. P., 10th Edn., IV, 1, Fig. 454; 9"' Kdn., Ill, Fig. -430), with thermometer . . . 0. Hi. 0 (•LMI5. -- idem, for demonstrating objectively. Figure 0. Id. (> lii'.llt;. Caloriscope after Lermantoff, Figure, for the same purpose !.<;.<) The, apparatus can also be used ;i^ ;i simple thermoecope. C'-M17. Apparatus after Foster, Figure (\V. I). Fig. 531 [504 1), tor showing that the liealiug effect on a conducting wire is proportional to (lie resistance and as the stpiare of the current . 1. Iti. o lii'.li*. Current Conductor of Silver and Platinum Wires soldered together (M. 1'.. K)"1 Kdu.. IV, I. Fig. 455; !)'" Kdn.. Ill, Fig. I:!'-': \V. D. p. S15 [754 |). for explaining the diffe- rence in specific resistance of two metals 0. 10. # It is also possible to show the heating effect of the electric current and the comparison of re- sistances heated by the current, by the aid of Kolbe's and Looser 's Thermoscopes ("Heat" Section'. <;LM lit. Calorimeter for demonstrating Joule's Law, after Friedr. C. d. .M filler (M. T. Fig. iM3) o. s. n (Ji'.iiiu. Calorimeter for demonstrating Joule's Law, for students exercises, after Halm, Figure (Halm. Schiilcriibungen. Fig. L'SJ), with thermometer 0.1-'. (I ci. J.vjc.. : 396, Joule's Law. 937 62 123. 1 : 10. 62124. 62 121. 1 : 5. 62 122. 1 : 6. 62 125. 1 : 0. H2.121. Current Calorimeter after Pfaundler, Figure (Fr. phys. Techn. II, 1, Fig. 459; £ •• :{. 509-1, 5!)81. o. :;. u 0. u;. (i 1. in. d 5090, 938 Voltaic Electricity. Section 4: Ohm's, Kirchhofi's and Joule's Laws. NIL I!'.' 129 — 62134. 1:5. 62 131. 1 : !). 62,129. Apparatus after I'ensder, F i g u r e, for showing the mode of action of heavy current £ fuses (Ztschr. f. d. phys. u. chem. U. 16, p. 84), with 3 glow lamps with fuses for the single lamps and for the groups 2. 10. o :>3,os2. Apparatus for Demonstrating the Arc in Vacuo, Figure, tubulated receiver with carbon holders and clamps 1. 12.0 62.131. Carbon Clamps as suggested by Dr. Uriisch (Liibeek), with 1 thick carbon and 1 carbon crucible, for use as electrical assay furnace, Figure, without the Runsen stand illustrated .' I. 12. o 62.132. Extra Carbons for above Kadi o. 0.3 62.133. Spare Carbon Crucible for above Kadi o. o. 6 <;•_>. l.'M. Demonstration Electric Melting Furnace for 20 — 30 amperes, Figu re, with horse shoe magnet; without melting crucible and protecting screen 7.10.0 The furnace is of iron with an inner clay lining- A fire-proof block provided with an adjusting screw can be moved up and down on the health of the furnace. This hearth block carries the small crucible, which is made of graphite, lime, niagnesite. etc. according to the operation to be carried out. The carbon electrodes, to which the current is conducted, project into the crucible. The furnace space is closed off by mica plates back and front, thus allowing the inside of the furnace and also the process of melting to be observed. By fixing a powerful magnet, as shown in the figure, the arc can he made to take the shape of a pointed flame The furnace is intended for 20— .'id amps, and ."ill — ~» volts. The carbons are HI mm in diameter cl. •>:,:',», sisii. f-'s. 3529, 521IO. No. BJ 183. Electric Furnaces. 939 62 144. 1 : 7. 62,13.5. One Pair Cables for above, each 1,5 in long, with cable lugs £ 0. 0. 0. 8. 0, 0. 5. 0 s. (1. (i. II 2. n 1. 0 0. 4 1. 0 6. o 0. 0 1 ri n Each further metre length per pair (>2.13(>. 10 Pair Carbon Rods 10 mm'diameter, 200 mm long 62.137. Melting Crucible of graphite, 40 mm diameter each 62.13S. Melting Crucible of magnesite, 40 mm diameter each 62.139. Protecting Screen with coloured windows 62,140. Electric Assay Furnace, Figure, up to 100 amps., without cable Carbons 500 mm long, 22 mm diameter; crucible 50 mm high, 40 mm diame 62. 141. 1 Pair Cables for above, each 1,5 m long, with cable lugs ter. Each further metre length for the pair 0, 0. 0. (i. 0 I. 0 1. 0 ii2.142. One Graphite Crucible, 50 mm high, 45 mm diameter 62,143. One Magnesite Crucible, 50 mm high, 45 mm diameter Electric Assay Furnaces with carbon adjusting device, Figure, tions, with mica window for observing the melting process. Current, amperes 100 150 for small 250 100 800 x 40 62,146 16. 10. 0. 2.0.0 0. 10. 0 62,150 0. 15. 0 62,154 0.4.3 150 62,158 0.3.0 melting opera- 500 150 1000 x 80 62,147 30. 0. 0 3. 10. 0 1.0.0 62,151 1. 10. 0 62,155 0. 15. 0 Capsule diameter, mm 65 or 100 65 or 100 Size of carbons, mm 500 x 22 750 x 30 List No 62144 B2 14S Price £ 11 0 0 12 10 0 One Pair Cables for above, 1.5 m long . £ 0. 15. 0 1. 10. 0 Each further metre per pair £ 0. 6. 0 090 Protecting Screen for above {^x»- ; £ ««* 62.H9 1 Pair Electrode Carbons {p">- - - £ 62,152 6^,153 Melting Capsules for Assay Furnaces Xos. 62,144 — 62,147. Diameter, mm 65 100 (List No 62 156 62 157 Carbon Capsules lprice £ 0. 1. 0 0. 1. 3 fList No 62 159 62 160 Magnes.te Capsules [Pri^ t «£»[ fff Maenesia Cansulps fList No 62<162 62'163 Magnesia Capsules (prioe £ 0. 3. 0 0. 6. 0 The electric furnaces require a minimum pressure of 60 volts. Series resistances are necessary, prices for these being quoted on receipt of particulars as to voltage available and requisite current strength. Cl. 129. 940 Voltaic Electricity. Section 4: Ohm's, Kirchhoff's and Joule's Laws. 62 165. 1 :- 8. 62 isa. i : s. 62 182. 1 : 6. 62 183. 1 : 4. Electrically Heated Laboratory Furnaces for high temperatures, horizontal pattern, Figure, with an inner porcelain tube heated by a spiral of thin platinum sheet; for maximum temperatures of 1400° C. List Tube Current Consumption Price of Furnaces (without Heatmg;mdRegulat instances TkT _ 1 -.J-1_ A. 1 -1 f\ 17" >i.ki k "\T _l_4: \ -C^«."U ^.1-1 ,^14-r* tvV J-J-" * • <*l' *J<£" * - No. 62165 62166 62167 length at 110 V. at 220 Y. 60 cm 22 Amps. 11 Amps. 44cm 16 Amps. 81/«Amps. 22 cm 10 Amps. (For 110 V. only) platinum) for both voltages 90 s. plus 9 g Platinum 85 s. plus TgPlatinum 75 s. plus 4 g Platinum 110 V. Price List No. Price 62168 £5.10 62169 £4.16 62170 £3.2 62171 £2.18 62172 £2.2 1 Gram Platinum, worked up in the furnaces; price (varying according to the state of the £ market) £ 0. 5. 0 to 0. s. n Larger Laboratory Furnaces and other Electric Furnaces <|iiot<-d for on application. Section 5: Electro-chemistry. As regards Apparatus after Liipke-Bose, Kohlrausch-Holborn and Hofmann, we shall be pleased to send separate price list on application. Voltameters. (iL'.lso. Water Decomposing Apparatus, simple pattern on wood stand. Figure, with graduated lubes ................................ i'.L'.181. -- idem, on iron stand. Figure ..................... (I. S. 0 o. ll!. o Xi>. IK 191. Voltaic Electricity. Section 5: Electrochemistry. 941 62 189. l 62 190. l : . Gas Measuring Jar for above, for simple volumetric determinations on gases . . . 62. is:. Eudiometer and Glass Cup (M. P., 10th Edn., IV, 1, Fig. 461 a; 9lh Edn., Ill, Fig. 339) 1. 0. 0 62.1SS. Voltameter for Objective Demonstration, Figure (W. 1). Fig. 528 [501]) . . . 0.12.0 02, 1 Sit. Voltameter (Bunsen's), Figure (M. I'., 10th Edn., IV, 1, Fig. 462; 9th Edn., Ill, Fig. 340) 0. 18. 0 O2.l!t0. Voltameter after Zwio.k, Figure 1. 6. 0 The apparatus serves for producing oxy-hydrogen j;as. for decomposing water (separating and measuring Imlrci^rn and oxygen), electrolysis of Glauber salt, decomposition of copper sulphate. 62,191. Voltameter, Figure, with variable level j 3.10.0 Cl. 4S«. •.'•-'!)(), 5873, 5864, 2290. 942 Voltaic Electricity. Section 5: Electrochemistry. NIL This voltameter is very well adapted for quickly checking ammeters. To fill it is only neressai \ to invert it. The bung should be removed when in use. 62.199. Voltameter after Friedr. C. G. Miiller, in glass jar for water cooling (M. T. Fig. 201) 0. 12. ti 62.200. Precision Gas Voltameter after Friedr. C. G. Miiller, F i g u r e (Ztschr. f. d. phys. u. chem. U. 14, 1901, p. 140; M.T. p. 288), for quickly and conveniently calibrating ammeters, also well adapted for practical school work. The apparatus can remain per- manently filled ready for use 2. s. o 62.201. Water Decomposing Apparatus for laryc quantities of oxyiren and hydrogen, F i g u r e, for potentials of 8—20 volts (M. P., 9th Edn., Ill, Fig. 449) . 3. 0. 0 62.202. Voltameter after (Jrimsehl, for catching separated gases; is inverted for filling; also suitable for practical school use (Ztschr. f. d. phys. u. chem. I'. 18. l'.'o:>, p. 2s:; Figs. 1 and la; Grimselil, Fig. 852) ' 0. 16.0 62.203. Gas Voltameter after Grimselil, for trapping the gases in general; of low resistance. rapidly decomposing with 3 — 4 volts (Ztschr. f. d. phys. u. chem. I". 18, 1905, p. 2SI. Figs. 2 and I' a) ' 0. 10. o Six of these apparatus can be used for demonstrating Faraday's first law (<•(. < 'liinsfhl. Fi.n. 850). Cl. 5959, 3482, 3481. 2304, 5380. No. 62215. Voltameters. 943 62 209. 1 : 6. 62210. 1:8. 62 212. 1 : 5. 62 213. 1 : 4. 62.204. Gas Coulomb-meter for practical school use, Figure (Hahn, Schiileriibungen, £ »• d. p. 381) 0. 12. 0 62.205. Copper Voltameter, Figure, with 2 copper plates and surface of 2 sq decimetres for 1 platinum plate, for a current of 5 amperes; without Platinum Plate 62.206. Platinum Plate for above, according to weight and state of market Approximately 62.207. Silver Voltameter, Figure, with rod-shaped silver anode, for a current density of 0.25 ampere- without Platinum Bowl (M. P., 10th Edn., IV, 1, Fig. 468) .... 62.208. Platinum Bowl for above, according to weight and state of market Approximately 62.209. U-shaped Decomposing Cell with platinum electrodes, after Friedr. C. G. Miiller (M. T. Fig. 204), Figure t>2,2lo. Electrolytic Apparatus after Grimsehl, with lead electrodes, Figure; chiefly for decomposing water with currents of up to 20 amperes (Ztschr. f. d. phys. u. chem. U. 16, 1903, p. 162, Fig. 3; Grimsehl, Fig. 846) 62.211. -- idem, with carbon electrodes, chiefly for generating chlorine 62.212. U-shaped Glass Tube with platinum electrodes and glass base, Figure (M. P., 9th Edn., Ill, Fig. 457; Gan.-Man. Fig. 717; Gan.-Kein. Fig. 946) 0. 8. 0 62.213. Copper Voltameter, Figure, after Friedr. C. G. Miiller (M. T. p. 290) 0. 8. 0 62.214. Copper Voltameter, Figure, with 3 copper plates of electrolytic copper . . . .11. 4. 0 62.215. Grooved Glass after Friedr. C. G. Miiller, with two electrodes each of copper, lead, carbon, zinc and platinum. The latter are clamped in with the aid of clamps No. 60,172, p. 799 (M. T. p. 291), without base clamps 1. 16. 0 I'l. 2540, 5823, 5985, 5825, 4171, S361 , 5901, 4323, 2309. 3. 10. 0 6. 0.0 3. 0. (t 3. 8.0 0. 10. 0 0. 10.0 0. 10. 0 844 Voltaic Electricity. Section 5: Electrochemistry. N.I. 62216 62216. 1:3. 62 217. 1 : :s. 62 221. 62 218. 1 : 10. 62220. 1 : 11. 62 225. 1 : 10. 62.216. Apparatus for Objectively Demonstrating Electrolytic Decompositions and Crystalli- £ zations, Figure (M. P., 9th Edn., Ill, Fig. 45!)) 0.14.0 62.217. Saturn's Tree Inset for above, Figure (M. P., 9th Edn., Ill, Fig. 460) .... 0. 4. 0 62.218. V-shaped Glass Tube with Platinum Electrode and stand, Figure (M. P., 9th Edn., III, Fig. 458) 0. IS. o 62.219. Electrolytic Apparatus after Griiusehl, with gas conduit tubes, for small currents (/tschr. f. d. phys. 11. chem. I*. 16, 1903, p. 162, Figs. 1 and 2), comprising 2 glass bell jars with platinum electrodes and 1 glass bell jar with carbon electrodes and a glass jar in which the glass bells are suspended • 12,220. Demonstration Experiment for Faraday's second Law, as suggested by A. W. Hofmann, Figure (M. P.. 9th Edn., Ill, Fig. 461), consisting of 3 water decomposing apparat uses. one with platinum and the others with carbon electrodes, for decomposing muriatic acid, acidulated water and liquid ammonia 3.1(1.0 t»L'. 221. Demonstration Experiment for Faraday's second Law, F i g u r e. without the ammeter illustrated; also without accumulator or current key (M. P., 10'" Edn., IV, 1, Fig. l.V.i) 3. 0. (I 62,222. U-shaped Decomposing Vessel after (Jrimschl, with water-cooling, for showing that in the electrolysis of dilute sulphuric acid the concentration of acid at the anode con- tinually increases and at the cathode continuously decreases (drimsehl. Fig. 847) . . 0. IS. 0 • 12.22.'!. W-shaped Decomposition Cell after (irimsehl. for showing the migration of sulphuric acid from the cathode to the anode (Crimsehl. Fig. S|S) . . . .' 1. (I. (I 112.221. Sliding Resistance for above, for no volts 1. l.o 112.225. Apparatus after Nernst for showing the velocity of migration of violet coloured Mn<), Ions, Figure (.M. I'.. 10"' Edn.. IV, 1. Fig. 472) ' 1. 4.0 •12,22(1. Apparatus after NYiedciiiann, for the Electrolysis of Salt Solutions and the Migration of Ions (.M. P., ll"1 Edn.. III. Fig. 151) 2.10.0 cl. :,»<•<•!. • ,3946, 6884, .Mil Electrolytic Apparatus. 945 62 231. 1 : 4. 62 229. 1 : 10. 62235. 1: 3. 62 232. 62.227. Electrolytic Demonstration Apparatus, after Hillig, for demonstrating the main pro- £ * (1 cesses in the electrolysis in the coloured solution of sodium chloride (Ztschr. f. d. phys. u. chem. U. 16, 1903, p. 222) 0. IS. (I 62.228. Electrolytic Demonstration Apparatus after Grimsehl, for explaining the mechanism of the transportation of electricity, after Hittorf (Grimsehl, Fig. 862) 0. 12. 0 ' 62.229. Apparatus after Hofmann, Figure, for proving that hydrogen and oxygen combine only in the proportion in which they are developed from water j 2. 16. 0 The apparatus consists of 2 U- tubes with 2 stopcocks, 1 similar tube with 1 stopcock and 3 brass stands on iron tripod with carriers and holders. 62.230. Apparatus for Electric Endosmose, U-shaped bent glass tube with porous partition wall (M. P., 9"' Edn., Ill, Fig. 464) 0. 3. 0 62.231. -- idem, for projection, Figure ; 0. 10. 0 Electrodes of sheet copper are inserted on both sides by means of rubber bungs, in a glass tube fixed horizontally on a board. A porous partition is fixed in the centre of the glass tube. A glass tube is filled on both sides and the narrow perpendicular glass tube inserted; the liquid then ascends to an equal height in both tubes. If now the current is introduced the liquid falls in one tube and ascends in the other. 62.232. Apparatus for Electric Endosmose, Figure, for connecting up to 110 — 220 volts I). 0. (M. P., 10th Edn., IV, 1, Fig. 527) ' 1. 4. 0 62.233. Apparatus after Wiedemann, for accurately measuring the liquid carried over to the ! negative pole (M. P., 9"1 Edn., Ill, Fig. 465), with copper cylinder 1. 10. 0 62.234. -- idem, with platinum cylinder 3. 0. 0 62.235. Mechanical Model for demonstrating Electrolysis, after Egyed, Figure . . . . i 0. 16. 0 A mechanical model for separating and displacing the electrolyte molecules by the electric current. < The atoms of the elements of which the electrolyte is comprised are each demonstrated as a quarter-circle. Each two of these combine to a semi-circle, which demonstrates a molecule of the elec- trolyte. The decomposition of the molecules is shown by the mutual displacement of the quarter- cire.les, so that on the left and right sides one atom each of the elements comprising the electrolyte are freed. Cl. 2546, 5808, 4254, 5680. 946 Voltaic Electricity. Section 5: Electrochemistry. 62 237. 1 : 4. 62 238. 1 . 4. 62 236. 62239. 1:4. 62,2.36. Mechanical Model for demonstrating the velocity of migration of the Ions, utter £ F. Kohlrauseh, Figure (Fr. pliys. techn. II, 1, Fig. 481) 2.10.0 62,237. Apparatus for demonstrating the migration of a drop of mercury by the inequality of surface tension produced electrolytic-ally, Figure, for projection 0. S. o 62,2.38. Capillary Galvanoscope, after \Yeinhold, for projection, Figure (W. 1). Fig. 5.30 [503]), with glass scale 0. 12. o 62,2.3!». Capillary Electrometer, after Ostwald, Figure, vertical pattern, on stand with holder, mirror, microscope, throe small tube's and 4 volt Osram lamp for illuminating 2. 10. 0 62,2 to. Precision Capillary Electrometer, after Ostwald, Figure, with fine universal ad- justment, on stand, with holder, microscope, mirror, and illuminating device for gas or with 4 volt Osram lamp. The illustration deviates somewhat from the pattern now constructed 10. 0.0 62,241. Capillary Electrometer, after Lippmann, Figure, with microscope' ((Jan. -Man. Fig. 651; (Jan. -Rein. Fig. 962) L5. 0. 0 02,212. Electrolytic Forge, Figure (M. T. p. 299) o. <;. o Tin- lieaUer is filled with a 10% solution of boiling potash and the lead plate connected witli the positive and the iron wire with the negative pole of a 110 — 220 volt network, a resistance bein^ inserted. When the iron wire is immersed to a distance of a few centimetres thr end is immediately rendered white hot and commences to dropoff. The current density should be approximately In amps. which is not sufficient l>y far to alone render the iron wire incandescent. .-.ll-.'l, •„'.•..-, I, •-'.'. N.I. t;-2 •>:,{<. Capillary Electrometers. Electrodes. 947 62 242. 1 : 5. 62241. 1:9. 62 246. 4 : 3. 62 249. 1 : 9. 62 244. 1 : 6. 62 250. 1 : 6. <;•_'. iM.'i. 2 Concentration Cells after Grimsehl, on one stand (Grimsehl, Fig. 863) lii',i'44. Electrolytic Stand t'ur Rotating Platinum Electrode, Figure; price, including motor and gearing, but excluding electrodes The one electrode is kept continually in motion by a 110 — 220 volt electric motor with cord and grin-ing: the elertrolytic processes are therefore not appreciably accelerated. We supply platinum electrodes and platinum dishes at as low a price possible, according to weight and with the addition of the* charges for shaping. (52,245. - - i d e m, with larger motor so as to enable the apparatus to be used as a Stirrer also 62,24(i. Flat Electrode, F i g u r e, for Laboratory experiments, with platinum sheet having ;i surface of 15x20 mm This electrode consists of a rectangular piece of the thinnest platinum foil welded on to two i'orksli;i|ii'd stiff platinum wires sealed in a glass tube; connection is made by a copper cord in the in- terior of the small glass tube. 62.247. - - idem, area 20x30 mm 62.248. — idem; area 30x40 mm <;_..! J!». Stand for above Platinum Electrodes, Figure. Price without Electrodes . . . . The rods on the insulating stand, for clamping the electrodes, can be adjusted both vertically :ui •-••ii 1. 0.0 1. 10. d $984, No. li-J 263. Galvano-plastic Arts. Galvano-plastics. 949 62 261. 1 : 4. 62 262. 1 : 6. 62 263. 1 : 7. £ 8. d. (ii','258. Complete Apparatus for Silvering and Gilding, Figure, comprising: 1 Bunsen cell, 1 enamelled dish, copper wires, copper, silver and gold hath, brush for removing grease, hand scratching brush, pumice stone, sawdust, scouring leather, and directions, in lac(|ueivd box ................................. j 1. 5. 0 (>2,ii5<). Complete Apparatus for Nickel-plating, Figure, comprising: 2 Bunsen cells, 1 glass trough 10x10x15 cm, 2 anode rods with clamping screws, 1 earthenware rod with clamping screws, leads, piepared Nickel Salts, Nickel anodes and nickel hook, brush for removing grease, pumice stone, sawdust, scouring leather, and directions, in lacquered box ..................... ........... 1. 4. 0 <;•_', 2<»<). -- idem, larger, with earthenware trough 20x20x20 cm ........... 1.15.0 Electrolytic Rectifiers: see p. 863. Section 6: Electro-magnetism and Electro-dynamics. Deflection of the Magnetic Needle. fi2,261. Oersted's Apparatus for the Deflection of the Magnetic Needle by the Electric Current, Figure (M. I'., !)'" Edn., Ill, Fig. 471 ; cf. Gan.-Man. Fig. 727; Gan.-Rein. Fig. 823), with 2 magnetic needles til', 262. - - i d e m, different pattern, Figure The apparatus has i> terminals so as to allow the most varied parts of the rectangle to act on the needles. 62,263. Apparatus with two astatically arranged Magnetic Needles, Figure, for showing deflection bv the electric current £ s. d. 0. 18. 0 0. 16. 0 0. 18.0 Cl. 2567, 2568, 5966, 2570. 950 Voltaic Electricity. Section 6: Electro-magnetism and Electro-dynamics. No. 62 204 — 62 264. 1 : 6. 62 265. 1 : 0. 62 266. 1 : 5. 62268. 1:7. 62 269 72. 1 : 8. 62 273. 1 : 6. 62.264. Apparatus for Deflecting the Magnetic Needle by the Electric Current, F i g u r e, £ comprising a voltaic cell, a brass stirrup and a magnetic needle on stand 0. Hi. n 62.265. Current Conductor for Experiments on the Deflection of the Magnetic Needle by the Electric Current, after Kolbe, Figure (Kolbe-Skellon, Introduction to Electricity, Part II, Fig. 105) 0. s. n Suitable Magnetic Needles and Stands for above: see Nos. 00,043 — 60,046 and 60,058, p. 786. Electromagnets. Unless stated to the contrary, the Electromagnets are provided with a winding of thick wire for connecting up with Bunsen Cells or Accumulators. 62,266. Magnetising Spiral, Figure (M. P., 9th Edn., Ill, Fig. 517), wood reel wound with wire '2 mm thick, with iron core which can be drawn out 0. Hi. u <;•_'. 267. — idem, smaller and wound with wire 1 nun thick 0. lo. o 62,268. Iron Bar on Stand and 2 Wire Spirals wound in contrary dierctions, F i g u r e, for showing the reversal of the magnetic poles when the current-direction is reversed . . 0. ll.'. 0 Electromagnets, Figure, horse-shoe shaped, with suspension ring and armature (cf. (lan.- Man. Fig. 7r>7; (ian.-Rein. Fig. 909). List No. 62,269 62,270 62,271 62,272 Length of Limbs mm 100 150 200 L'.MI £ 0. 8. 0 0. 12. 0 0. 16. 0 0. 20. 0 The, armature is fastened to a chain, as suggested by Grimsehl, to prevent its falling down. 62.273. 2 Coils with winding of different thickness, with handles, and with 2 solid, 2 hollow soft iron cores for same; 2 hollow cylinders of thin sheet iron, 1 steel wire bundle and 1 soft iron wire bundle, Figure, after Friedr. <'. (',. Miillei (M. T. Fig. 187), for electro- magnetic experiments 1. (1.0 Solenoid on Stand for Electro-magnetic Experiments with the Hartl Pointer Malance: see Xo. 51,600, p. 2-10. ( 'I. ,-i973,2572,2.'>73. •.'.•>•!. 2576,4166. .No. l!-.'-JTS. Electromagnets. 951 62 277. 1 = 9. 62 278 A. 1:9. 62 278 B. 1:9. C>1'. L'74. Joule's Electromagnet, with broad, flat pole surfaces (Kolbe-Skellon, Introduction to Electricity, Part II, Fig. 104 B), of horse-.shoe section, with suspension rings and armature, Figure; carrying capacity when supplied with current by an accumulator or a bichromate cell, about 120 and 70 kg respectively; own weight 1 kg !7.r>. Elektromagnet, Figure, with suspension ring and armature Tin- electromagnet carries 50 kg. !7(i. Electromagnet carrying 50 kg, in wood frame, F i g u r e, arranged to rotate about the horizontal axis, with armature, balance pan and armature chain (Gan.-Kein. Fig. 1(07) As the electromagnet run be removed from the fillet by loosening two screws it is possible to u*e tin- magnet alone — without frame. <>2,277. Electromagnet carrying 100 kg, F i g u r e, in wood frame, with limbs 250 mm long, armature and balance pan The armature is, as in the preceding item, fastened to a chain in accordance with Grimsehl's suggestion. '2 '278 B. I £ s. d. 0. 18. 0 1. 4. d 1. 4.0 1 . 18. 0 2. 4.0 Cl. 3472, 2577, 2579, 2580, 2578, 2581. 952 Voltaic Electricity. Section 6: Electro-magnetism and Electro-dynamics. 62 280. 1 : 4. 62 281. 1 : 6. 62 282 B. 1:6. 62.279. Electromagnet carrying 150 kg, Figure, with lever stand for measuring the car- t rying capacity (M. P., 9th Edn., Ill, Fig. 520) . . " mm length of side for holding on air currents when the bars are swin^inj;. 02.2s.'i. v. Waltenhofen's Pendulum, Figure, for showing the damping effect of induction, with plain and toothed copper piece 2. Id. o ('•2,28-1. Foucault's Rotating Copper Disc, Figure, with wheel gearing, for demonstrating eddy currents and the heating of the disc when rotated between the magnetic poles .'{. 0. d CLU8S,M00, ..I-".!, 2585, 2591. N... (!•.> -.'si. Electromagnets. 953 62281,62286. 1:6. 62 288, 62 282, 62 283, 62 287. 1 : 10. 02.285. Silver Coin with Pyramid Mirror, after Tyndall, for showing damping of a metallic £ s body when rotated in the magnetic field, Figure (Tyndall, Heat [Die Warme]r 4'h German Edn., p. 87), with suspension device 1. 4. 0 62.286. Device for Melting easily Liquefying Metals by rotating in the magnetic field, after Tyndall, Figure (Tyndall, Heat [Die Warme], 4lh German Edn., p. 91) 4. 10.0 A copper bush filled with solid metal is rotated rapidly between the pole pieces of an electro- magnet; after short time the metal is melted by the eddy currents present. 62.287. Polarisation Apparatus, Figure, for showing the Rotation of the Plane of Polari- sation by magnetizing forces, with two nicols 12 mm, one double quartz plate and divided circle with index; Faraday Glass Parallelepiped 70x18x18 mm, in box with two pierced pole pieces j 5. 0. 0 Bismuth Spirals for measuring Field Density: sec Nos. 62,306 and 62,307, p. 956. 02.288. Large Electromagnet, V i g u r e, for all paramagnetic and diamagnetic experiments, with magnets vertically arranged, with 4 coils with device for putting the windings in series or parallel, with commutator and interrupter, frame running on rollers. Length of magnel cores 430 mm, diameter 67 mm; length of each coil 200 mm, diameter 130 mm; with massive pierced pole pieces and two pair differently shaped conical attachments for same 30. 0. 0 The electromagnet is constructed for momentary loads of 30 amps, which are applied when tin- windings of the electromagnet are in series and connected direct to 65 volts D. C. working pressure. If the working pressure is 110 volts a proportionate resistance should be inserted in series. If desired, and at an extra cost of £ 1, the electromagnet is also supplied for connecting direct on to 1 10 or 220 volts. The maximum current density is then correspondingly lower, but the number of windings higher, so that tin- total number of ampere-turns is approximately the same. As Accessories we recommend the same as those for Electromagnet No. 62,281; the prices being the same as in that case. Cl. 2592, 2593, 2588, 2586, 2587, 2589. 954 Voltaic Electricity. Section 6: Electro-magnetism and Electro-dynamics. No. 62 2X9 — 62 290. 1 : 10. 62282C. 1:8. 62 283 C. 1:8. 62 284 C. 1:10. 62 285 C. 1 62 286 C. 1:8. 62,289. Electromagnet with Vertical Magnet Limbs, somewhat smaller pattern; magnet limbs 350 mm long and 52 mm diameter; length of each coil 160 mm, diameter 100 mm . 22. 10. o The junction with electromagnet is built for a maximum momentary current density of 25 amperes in con- ith 65 volts. As regards other voltages and accessories, the same remarks hold as for No. 62.-JSS. 62,290. Large Electromagnet after Ruhmkorff, F i g u re , for para- and diamagnetic ex- periments, with horizontal magnet limbs 70 mm diameter and 220 mm length, pierced for taking the polarisation apparatus; coils 200 mm long and 130 mm diameter, with two pair different shaped pole-pieces, with pole commutator and interrupter (M. P., 9'" Edn., Ill, Fig. 854) 25. As to current density and voltage all the remarks made under No. 62,288 hold good here also. The accessories are also the same as for No. 62,281 and are supplied at the same price. Figs. 62,282 C to 62,286 C show the construction of these accessories for No. 62,290. 62,291. Electromagnet, Figure, with arrangement for enabling the magnet limbs to be used vertically and horizontally: coil 150 mm length, 120 mm diameter; magnet limbs 170 mm long, 60 mm diameter As regards current and voltage, also accessories: cf. remarks under No. 62,288. 02.292. Large Half-ring Electromagnet after du Bois, cf. Fig. 02,299, p. 950; with arc-shaped magnet limbs on a massive base-plate forming the yoke; with one pair cylindrical and one pair conical pole pieces, one distance piece for 1 mm pole distance of the conical pole pieces, Stand and Spanners (Ztschr. f. lust rumentenkunde. 1899, p. 357). ... 1 By loosening the fixing screws the limbs can be moved apart and rotated with reference to each ( '1.2595, 2596. 2598, 2599,2600,2601. 2-1. 0.0 0. 0 Nn. H-2'298. Electromagnets. 955 62291,62282. 1:7. 62 294. 1 : 4. 62 296. other. The entire magnet can be tilted over and employed, in conjunction with the levelling screws supplied, with lines of force running perpendicularly. The stage fixed between the magnet limbs is rotary, can be adjusted in the plane and can also IK- screwed in laterally in the baseplate. 2 iron cores are inserted above in the magnet limbs and can removed for optical experiments. The winding is arranged for 20 amperes, consists of 2500 turns, and when in series has a resistance of approx. 3.3 ohms and is intended for connecting up to 65 volts. With the . (inical pole pieces the pole distance is about 1 mm (30 sq. mm cross section) and with -lo.uiMi ampere-turns the field is approx. 38,0(Hi gaii**. Accessories for preceding Electromagnet. t;iM'<»:}. One Pair Cylindrical Pieces of Dynamo Steel with attachment pieces worked in, for making further pole pieces ii'J.L'04. Universal Slider with rotating plate and correcting device, niicroinetrically adjustable in both planes, Figure <;:.'. L".tr>. v. Waltenhofen's Pendulum with gallows and interchangeable suspension for various objects (iL',L".M). Flat Induction Coil of about 5 mm diameter, with intermediate pole piece, F i g u r e, for measuring field-densities with a ballistic galvanometer . (i This magnet is constructed in a similar manner to No. 62,292 but is of only half the linear dimensions. The -winding is arranged for 8 amps., and when the coils are in series tin- resist mice i-; approximately 4 ohms; the apparatus can therefore be conveniently connected up to 32 volts. Accessories for preceding Electromagnet. 62.300. One Pair Cylindrical Pieces for making additional pole pieces, of dynamo steel . . 62.301 . Universal Slider, cf. Fig. 62,294 , . 62,302.' v. Waltenhofen's Pendulum .62,303. Flat Induction Coil, cf. Fig. 62,296 62,304. Polarisation Apparatus with divided circle and Faraday's Glass Block 02,3or>. Holder for a Bismuth Spiral 02. .">()(>. Bismuth Spiral after Lenard, F i g n r e, for determining the Field Density of Magnetic Fields by the change in the Conducting Resistance which bismuth undergoes in the field; in case, with calibration curve; approx. 20 mm diameter • 62,3d7. - id e in, 5 to 6 mm diameter The bismuth spirals afford a very convenient means of measuring the field-densities by means of a resistance measurement with a \Vlieatstone Bridge. The thickness of the spirals is only about 1 mm so that they can be introduced into very narrow fields, e. g. between armature and pole pieces of a dynamo. An average change of resistance of .">",, is produced by 1000 lines per sq. cm: accurate data can be obtained from the calibration curve supplied with each spiral. 111',. ''.OX. Electromagnet after Prof. P. Weiss, with coils for water cooling which can be loaded twice as much as in the ease of air cooling; F i g n r e; diameter of pole pieces 1(10 mm; with one pair cylindrical and one pair conical pole pieces; on stonl wood board . . S7. in. O The pole pieces can be adjusted by a micrometer motion. The coils are arranged as near as possible to the pole pieces and the cross section of the iron increases steadily from the pole pieces up to the centre of the magnetic circuit, so that leakage is avoided as much as possible and a very high degree of magnetization attained. I'nless otherwise requested the winding U dimensioned for 120 volts. A great advantage lies in the fact that the entire apparatus remains quite cool. 02.309. -- idem, arranged to rotate on iron base so that the magnet can easily be placed 1. 10. 0 I. l.V 0 3. 0. 0 :;. o. o 7. :>. o o. HI.O 3. o. o 3. o. o in any position, with horizontal divided circle Hi.'.. '110. Electromagnet after Prof. \Veiss, as No. 02.30H, but with pole pieces 92 mm diameter 62,311. — idem, on tripod, as No. 62,309 in:,, o. o 73. 10.0 s.v it. o CI. .-.CHI. .-.ilSIl, lilt I Electromagnets. 957 62 314. 1 : 6. 62 316. 1 : 9 62317. 1:3. 62 319. I : 9. 62.312. Electromagnet after Prof. Weiss, as No. 62,308, but with pole pieces 80 mm diameter 62.313. --idem, on iron base, as No. 62,309 The Weiss Electromagnets Nos. 62,308 — 62,313 can be fitted with the same accessories as the Half-ring Electromagnet No. 62,292 for the same price. 62.314. Band Spiral for magnetizing (M. P., 9"' Edn., Ill, Fig. 526), Figure 62.315. Apparatus after Wertheim, Figure, for the singing of steel when magnetized (M. P., 9th Edn., Ill, Fig. 530) 62.316. Apparatus after v. Waltenhofen, Figure (M. P., 9th Edn., Ill, Fig. 891 ; Fr. phys. Techn. II, 1, Fig. 650), for demonstrating saturation, in accordance with which thin iron tubes become more magnetic at low current densities than massive bars; the reverse takes place, however, when the current densities are high 62.317. Electromagnetic Motor after Eitchie (Ritchie's Top), Figure (M. P., 9th Edn., Ill, Fig. 540) Contrary to the illustration the apparatus is constructed with a 4-pole armature. 62.318. Electric Motor after Ritchie This is constructed exactly like the preceding, but it has an electromagnet instead of the per- manent magnet. 62.319. Electromagnetic Motor after Page, Figure (M. P., 9th Edn., Ill, Fig. 607), with 4 upright coils £ s. d. 52. 10. 0 62. 10. 0 1. 4.0 2. 10. 0 4. 10. 0 1.10. 0 1. 12.0 Cl. 1050, 5972, 2606n 2608. 6. 0.0 2607, 958 Voltaic Electricity. Section 6 : Electro-magnetism and Electro-dynamics. No. (W320 — 62 321. 1 : 3. 62 320. 1 : 5. 62 323 A. 1:6. 62 324. 1 : 4. 62 322. 1 : 4. 62 325. 1 : r,. (iLViL'O. Electromagnetic Motor after Froment, Figure (M. P., !»'" Kdn., III. Fig. 542), large pattern . <> 62.321. Electromagnetic Motor for rotating (leissler Tulies (if up to L'O cm length, F i g u re, without tube illustrated ()- "'• " 62.322. Electromagnetic Motor with suction pump, Figure -. <>- <» Electro-magnetic Telegraphy. r,-_'.:iU3. Needle Telegraph, Figs. A and H, with a signal transmitter and a receiver, letters visible at a distance . •'*• 1°- ° (il',324. Morse Telegraph, Figure, small, for rotating with the hand All Morse Telegraphs have a coloured |>in in pliu-e of the ordinary printing pin. the resultant \vritini; appearing in colour. I 'I. •.'•i(l», 2613.2610. JlilL', -.'ill 4. 923, 5908. No o-.' :!;;•.'. Electro-magnetic Telegraphy. 959 62 327. 1 : 4. 62329. 1:5. 62328. 1 : 7. 62.325. Morse Telegraph for Schools (Ink Writer), with open clockwork, key, and wet cell, Figure 02.326. - - i d e m, without cell 62.327. Morse Ink Writer, Figure, with clockwork under glass, on polished mahogany hoard (ef. Gan.-Man. Fig.' 847; Gan.-Rein. Fig. 925) 62,32X. Model of a Telegraph Station, F i g u r e, comprising a Moise Ink Writer, a compre- hensive relay, a .Morse key and a galvanometer with open wire connections to show plainly the course of the current. The connections are so arranged that the station \\oiks in itself. If desired the connections are so arranged that two such stations can he worked reciprocally 62,329. Standard Ink Writer for direct Printing, model of the Prussian State Eailway, Figure, with reinovahle spring drum, horizontal detachable paper roll in the base; on polished mahogany board, for open current; resistance of magnet coils 15 ohms . . •12, 330. Extra price for insulated translator pillar t>2,331. Extra price for adjustable magnet system 62,332. Extra price for automatic release, especially for wireless telegraphy £ s. . «-' 340 — 62 347. 1 : 3. 62 349. 1 : 3. 62 346. 1 : .V 62,340. Morse Telegraph for instruction purposes, F i g u r e 2 stations together £ s. (1. I). 111. 0 On a polished stand are conveniently arranged the Morse Apparatus with clockwork under gla«s, the key, a porcelain insulator and a cell, and provided with different coloured leads. By this arrange- ment and the employment of two stations the understanding is aided considerably in following the processes of telegraphing. 62.341. Morse Telegraph for instruction purposes as preceding, without clockwork, for rotating with the hand by means of wheel gearing. 2 stations together 5. '0. 0 62.342. Morse Telegraph, as No. 62,340, each station with relay for open circuit and provided with 2 cells. 2 stations together ' 10. 0. o 62.343. Morse Telegraph, as No. 62,341, each station provided with relay for open ciicuit and with 2 cells. 2 stations together ' 8. 10.0 61,147. Morse Key, Figure on p. 868, fitting apparatus Nos. 62,324—62,327 (Gan.-Mau. Fig. 846; Gan.-Rein. Fig. 927) 0.10.0 62.34-1. Morse Key, large pattern 1. o.o Morse Keys for heavy current; see "Radio-telegraphy" Section. 62, .'545. Polarised Relay, Figu re, in metal case with glass lid, for telegraph purposes, for open or closed circuit current '. 3. 0. 0 (J2.346. Polarised Relay, highly sensitive1. Figure, with resistance of approximately 7000 ohms, chiefly for wireless telegraphy, for open or closed circuits !). 0. 0 62.347. Relay, Figure, very comprehensively arranged, can be used on closed or open circuits (cf. Can. -Man. F'ig. 853; (lan.-Kein. Fig. !»28) 2. '8.0 62. 3 IN. Polarised Relay, simple, with adjustable sensitivity, resistance l.'iO ohms, in walnut case, for closed or open circuit working. Figure 1 . o. 0 Cl. 20'JO, 5832, 59'', -'«-'•.', •-'824, 58 ''.31150. No. 62359. Telegraphy. House Telegraphy. 961 62 350. 1 : 8. 62 358. 1 : 4. 62355. 1:3 62 359. 1 : 4. 62351. 1:8. 62 357. 1 = 5. 62.349. Simple Relay for closed or open circuit, F i g u r e, approx. 100 ohms resistance 62.350. Electric Bell, fitted with key on stand, Figure 62.351. Electric Bell, Figure, on stand (Gan.-Man. Fig. 852) The bell can be arranged either as a striking or trembling bell. In the first case the two terminals visible to the left of the figure are used, these leading to the magnet winding; in the latter case the two outer terminals are connected, thus putting into circuit the automatic interrupting device of the bell. Electric Bells, .for House Telegraph Connections, in polished walnut case List No. 62,352 62,353 62,354 Diameter of Bell Dome 60 80 100 mm £ 0.2.0 0.2.6 0.4.0 62.355. Electric Bell with indicator disc drop and continuously ringing contact, Figure 0. 7. 0 For suitable Cells for House Telegraphs: see Nos. 60,787—60,800, p. 850. 62.356. Waxed Wire for House Telegraph and Ivxpci iniental purposes, 0,9mm copper dia- meter, approx. 170 m to 1 kg. Price per kg 0. 4. 0 62.357. Alternating Current Bell in walnut case, for working with magneto generators; internal arrangement similar to Fig. 62,357 0. 10. 0 f 62.358. Magneto Generator for alarm installations. Figure, open, with two magnets, with automatic short circuiting contact by displacing the crank axis I 0. 15. 0 62.359. Magneto Generator, with three magnets, Figure, German Post Office pattern, Figure 1. 3. 0 Cl. 1027, 57 r, 61 r, 62 >% 2628, 63 f. 61 £ S. d. 0. 6.0 0.16.0 0. 8. 0 962 Voltaic Electricity. Section 6: Electro-magnetism and Electro-dynamics. No. 62 360 — = 62 360. 1 : 4. 62 365. 1 : 4. 62 361. 1 : 4 62 367, 62 368. 1 : 4. 62 369. 1 : 5. 62,360. Magneto Generator with five magnets, Figure 1. in. o 62.361. Magneto Generator, large, with six magnets, Figure 3. 5.0 62.362. Sections of Telegraph Cables, for subterranean and submarine laying, each £ 0. 10. 0 to £ 1. 0. 0. Apparatus for Phototelegraphy, Prof. Korn's system, constructed by us, quoted for on application. Theory of Lines of Force. 62.363. Wood Frame, 400 mm side, stretched with cardboard, for demonstrating lines of magnetic force, with sieve and filings, for use with permanent magnet and electromagnets 0. 3. 0 62.364. 20 Steel Spheres, 3,5 mm diameter, for demonstrating lines of force curves (\V. I). Fig. 549 [522]) 0. 2. 0 62.365. Apparatus after To'pler, Figure, for demonstrating objectively the existence of the magnetic curves between the poles of an electromagnet 1. 4.0 The glass trough is filled with glycerine, and finely powdered iron (previously uniformly mixed with sonic glycerine) is distributed in same. The curves form when the circuit is closed. 62.366. Model for explaining the Direction in which the lines of Magnetic Force encircle a Conductor (W. D. Fig. 548 [521]) 0. ir>. o 62.367. Wire Coil, can also be used for Ampere's stand No. 62,383, Figure (W. l>. Fig. 537 |510|), without /.inc plates 0. 8. 0 62.368. Zinc Plate for above, in two parts, for producing lines of force, F i g 11 r e, to be used in conjunction with No. 62,367 (W. D. Fig. 547 [520]) 0. 4. 0 ( 1.60 f, 64 r, 5869, MM. MSI No. 6-2370. Magnetos. Theory o! Lines of Force. 963 B <£> H N Q R 62 370. 1 : 8. i;.!,:3t)<). Apparatus for demonstrating the Lines of Force of Current Conductors, sifter Bauern- berger, Figure »iL'..'>70. 1 Set Apparatus for explaining the Lines of Force Theory, after Berghoff, Figs. A — 8 For producing the magnetic fields use is made firstly of needle-shaped magnets and secondly of copper wires, traversed by tin- current, and bent to correspond. The former are enclosed between two glass plates size 130 x 180 mm: in the latter case a glass plate of the. same size is mounted in a wood frame and drilled out to correspond with the shape of wire; the wood frame also carries the terminals for connecting ui) ''"' current. Constructed in this manner the apparatus are durable and can be easily cleaned. By strewing iron filings on the glass plates the lines of force can be demonstrated visibly. We recommend for use in these experiments ordinary iron filings carefully strained to different sizes; it is less advantageous to use ferrum alcoholisatum. The following pertain to the complete set: (1)1 bar magnet, Fig. A; (2) 2 magnets, the opposite poles being opposite each other, Fig. B; (3) 2 magnets whose similar poles are opposite each other, Fig. C; (4) horse-shoe magnet, Fig. D; (5) 2 parallel magnets whose poles of similar name are alongside each other, Fig. E; (6) 2 parallel magnets whose dissimilar poles are alongside each other, Fig. F; (7) deformation of lines of force. Fig. G and II; (8) homogeneous field, Fig. J and K; (9) magnetic field of a current, Fig. Ij and M; (10) magnetic field of a current perpendicular to direction of current. Fig. N; (11) magnetic field of two parallel currents flowing in opposite directions. Fig. 0; (12) magnetic, field of two parallel currents flowing in same direction, Fig. P ; ( 13) magnetic field of a number of circuits in series (of a solenoid), Fig. Q; (14) solenoid with a number of windings, Fig. R: (15) earth's magnetic field, Fig. 8. For objective demonstration it is necessary to use an Apparatus for horizontal pro- jection (List Nos. 51,032 to 51,039) or a Megadiascope. £ s. d. 0. 18. 0 4. 0. 0 Cl. 372-38T. 61* 964 Voltaic Electricity. Section 6: Electro-magnetism and Electro-dynamics. N... M371 — 62 371 A. 1:7. 62 371 C. 1:6. 62 371 D. 1:30. 62 372. 1 : 8. 62 373. 1 : 12. 62 374. 1 : 10. 62,371. Apparatus for explaining the Theory of Lines of Magnetic Force, after s/ymansky, £ Figs. A — I) (Ztschr. f. d. phys. u. ehem. I'., 7, p. 10). The host galvanometer to use- is S/ymansky's, No. 61,342 ' 3. Id. 0 (1) Horse-shoe shaped electromagnet Fig. A. t-2) 2 Attachments for the magnet and 2 small rectilinear adjustable parallel slide rails with •_' sni;ill sliding conductors, nickelled, Fig. 6. (3) 1 Set lines of force rails, Fig. A, nickelled. (4) Diverging slide rails with sliding conductors, nickelled. Fig. C. (5) 2 Large slide rails with large sliding conductor, for explaining the earth's mamietic field, nickelled. Fie. D. 62,372. Apparatus for Demonstrating the Lines of Force Image of Lineally Directed Currents, perpendicular to the axis, after Fricdr. C. (1. Miiller (M. '!'. Fin. 173), F i <; u r o . . 62,374. Apparatus for Demonstrating the Magnetic Field of Lineally Directed Currents, after (lot/o, with two magnetic noodles, Figure II. 12. d 62,373. 2 Sheets Cardboard with eoiulnetin.u wires, after Friodr. C. (1. .Miillor (M. T. p. 253), for demonstrating the magnetic field of straight and In-lit conductors parallel to the axis, F i jr u r e d. 2. 1. Id. d ( '1. 2056, 2657, 2658, 2(i5», 4811, 4141, 414.'. 4 I '.".I. NIL (i->381. Theory of Lines of Force. 965 62 376. 1 = 6. 62 379. 1 : 6. 62377. 1 = 11- MAX KOHL CHEMNITZ 62 380. 1 : 4. Mf'MNMfffift J 62 378. 1 : .-,. 62 381. 1 : 5. 62,37~>. 2 Wire Coils on wood frame, for demonstrating the magnetic fields of a single con- ductor, of two parallel currents in the same and two parallel currents in opposite direc- tions (W. u. E., phys. prakt. 4th Edn., p. 492). A current density of only 1 — 2 amps, is necessary : £ s. (I. 2. 5. 0 0. 18. 0 62.376. Apparatus for the Magnetic Field of a Circular Current, Figure 62.377. Demonstration Apparatus for Field of an Annular Conductor, after Gotze, with five magnetic needles, Figure ; 2. 10. 0 62.378. Apparatus for Demonstrating the Multiplication of the Current Effect when a Magnetic Field is generated, after Friedr. C. G. Miiller, Figure (M. T. Fig. 176), with a single and a quintuple coil 0. 10. 0 62.379. Demonstration Apparatus for the Magnetic Field of a Solenoid and of a bar-shaped Electromagnet, after Gotze, Figure. The iron core can be taken out 3. 10. 0 62.380. Apparatus for Demonstrating the Flow of the Magnetic Field in a Solenoid, after Bauernberger, Figure 1. 4. 0 62.381. Apparatus for the Magnetic Field of a Solenoid, after Friedr. C. G. Miiller, Figure (M. T. Fig. 177) 0. 10.0 Cl. 5549, 4116, 4107, 3558, 3878,6012. 966 Voltaic Electricity. Section 6: Electro-magnetism and Electro-dynamics. 62 382. 1 : 8. 62 383. 1 : 6. 62 387. 1 : .-,. 62 386. 1:10. »;:.'. 3*2. Demonstration Apparatus for the Magnetic Field of a horse-shoe Electromagnet, after *•' Gotze, Figure l.ln. <> 112,383. Ampere's Stand, Figure, reliable pattern, with separate stands; main stand on metal tripod with levelling screws, rotary and fixed in position by screw; wire fignrc.-. of aluminium with silver points. The following appertain to above: 1 solenoid (\V. I). Fig. 536 [509]), 1 simple rectangle (\V. 1). Fig. 531' [505]). 1 double (astatic) rectangle (W. 1). Fig. 534 [507]), 1 wire stirrup with wire coil (W. D. Fig. 535 |508|), 1 boxwood bowl with - concentric rings, I boxwood bowl with partition wall. Also adapted for experiments as suggested in (Ian. -.Man. Figs. 739, 740, 746, 751; Gan.-Rein. Fiirs. S'.tl. 893, 877 4. 4. 0 This pattern enables the experiments lo succeed with ease. Tne primary condition is that absolutely pure and dry mercury should be employed. This we supply if desired at a charge of £ 0. 8. 0 per kilo. A current density of 1.5 — 'Jo amps, is necessary. Precise instructions for use arc jjiven in. »;2,3t!7. Wire Coil for Ampere's Stand (W. D. Fig. 537 [510]), Figure on p. 962 I). S. It (I. •.'(•,73,3878, 2675, 267. No. 62 390. Ampere's Stands. 967 62 389. 1 : 5. 62388. 1:12. 62 390. 1 : 4. 62, 368. Zinc Plate, in two parts, for demonstrating lines of force, for vise in conjunction with No. 62,367 (W. D. Fig. 547 [520]) (iL'..">sf;. Ampere's Stand, large pattern, Figure, with aluminium solenoid working on sapphire rap; height of stand 75 cm. The lateral flat wire coil moves in hinges, as does also the lower wire holder The apparatus works very well with a few Bunsen Cells and permits of proving the laws of attraction and repulsion of currents flowing in the same and opposite directions. 62.387. Ampere's Stand, simple, Figure, with a rectangular, a circular, an astatic and a solenoid-shaped conductor 62.388. Apparatus after Friedr. C. G. Miiller, for demonstrating the electro-dynamic action upon each other of currents flowing in the same and opposite directions. F i g u r e, com- prising two bundles of Lametta strips stretched between terminals, and a Eoget spiral (M. T. Fig. 214) <;.;. is(.». Apparatus after .Miihlenbein, Figure for demonstrating the alternating action of currents and magnets (Ztschr. f. d. phys. u. chem. U., 1, p. 203) The apparatus admits of proving Ampere's Laws easily and visibly for teaching purposes. 62,390. Apparatus for Muhlenbein's experiment, Figure, after Kolbe (Kolbe-Skellon, Introduction to Electricity, Part II, Fig. 96), consisting of 1 wire frame on wood board (No. 62,392, £0.15.0), I'Ruhmkorff Commutator (No. 61,135, £1.5.0) and 1 movable Conductor as suggested by Miihlenbein (No. 62,391, £0.15.0) £ s. d. 0. 4. (I 7. 10.0 1. 10. 0 1. 16. 0 2. 14.0 2. 15. 0 Cl. 2676, 3887, 395G. 968 Voltaic Electricity. Section 6: Electro-magnetism and Electro-dynamics. No. 02391 — 62404. 1 : 10. 62 400. 1 : 10. 62403. 1 : 13. 62.391. Movable Conductor after Miihlenbein, cf. Fig u r e 62,390, suitable for placing in £ s. d. the terminals of the commutator Xo. 61,135 0. 15. o 62.392. Wire Frame on Wood Board (Kolbe-Skellon, Introduction to Electricity, Part II, Fig. 96) for Miihlenbein's experiment, cf. F i g u r e 62,390 ' 0. IT., o 62.393. Ampere's Stand, after Kolbe (Kolbe-Skellon, Introduction to Electricity, Part II, Fig. 98) ' 1.15.0 For above: 62.394. Simple Solenoid \\illi pointer (Fig. 98 B) 0.12.0 62.395. Tenfold Solenoid 0. 14. o 62.396. Curled Solenoid (Fig. 101) o. 12. o All solenoids have platinum points. 62.397. Fixed Wire Frame (Fig. 98 B2) on slider, with two adjustable current-direction indicators 1. o. 0 62.398. Tenfold Wire Frame for placing in the -slider; can also be used for demonstrating the multiplier 1. o. o 62,:5!»9. Magnetic Needle (Fig. 110) with glass tube, on slider o. 12. o 62.400. Universal Stand, after Kolbe (Kolbe-Skellon, Introduction to Electricity, Part. II, Figs. 98—101, 110, 111, 137), Figure (Ztschr. f. d. phys. u. chem. F/8, 1894/95, p. 155) s. 0. 0 The following pertain to the apparatus: (a) 'The Stand (Fig. 98 A or 110 A). (b) Parts to enable it to be used as an Ampere stand (Figs. 98 — 101 ): the movable conductors of aluminium with platinum points; all current conductors with adjustable current direction indicators. (c) Parts for the model of a multiplier and a tangent galvanometer (Figs. 110 and 111). (d) Parts for the sensitive galvanometer (Fig. 137), with astatic needle and copper damper, also an insertion mirror; for showing thermo-electric currents (Fig. 135) and magnetic induction (Figs. 138—140, 148). (e) 1 Zinc Protecting Box with two glass walls, for finer experiments with the mirror. (f) 1 Box for storing the solenoids, needles, etc. 62.401. 1 Accurately Ground Mirror for No. 62,400 Extra o. 12. n 62.402. 1 Double Needle with 2 unidirected magnets for No. 62,400 Extra 0. s. u 62.403. Square Conductor for explaining Ampere's Rule, F i g u r e, after Friedr. ('. (!. Miiller (M. T. Fig. 180) 0. li. o »J2.lol. De la Rive's Floating Current, F i g u re (M. P. 9'h Edn. Ill, Fig. 602; (ian.-Uein. Fig. 884), without glass vessel or magnet 0. S. I) 62,40."). Rotary Solenoid with Iron Stopper, Figure, after (Jotxc, tor demonstrating the action of a magnetic field on the position of the solenoid \\liicli is traversed by the current 4. 0.0 62.406. Apparatus for demonstrating the Alternating Effect of Crossed Currents, after Fried r. C. (i. Miiller, at the same time a model of a dynamometer (M. T. Fig. 215) .... .'{. 12.0 62.407. Apparatus after Buff, Figure, for the attraction of parallel unidirected and the repulsion of parallel opposed currents (M. P. 9"1 Kdn. III. Figs. "()»> and 707) ... 2. lo. o Cl. 2673, 2078, 4155. No. 6'.' 412. Interaction of Currents. 969 62407. 62.408. Roget's Spiral for the Attraction of rectified parallel Currents, Figure 02.409. Apparatus after Garthe, Figure, for the action of crossed currents (M. P. 9lh Edn. Ill, Fig. 712) 02.410. Electro-dynamic Double Pendulum, after Kolhe, Figure, for showing the mutual attraction and repulsion of conductors and magnets (Ztschr. f. d. phys. u. chem. U. 23, 1910, p. 201) This newly-designed apparatus is very certain in its action and requires a current of only -2 — 3 amps. at li — 8 volts. A special advantage of the apparatus rests in the fact that one of the solenoids can be turned through 180" so that the current flows in an inverse direction in relation to the other solenoid or the magnet, without a commutator being necessary. 62.411. Barlow's Wheel, Figure (M. P. 9th Edn. III. Fig. 577; Gan.-Eein. Fig. 886) . 62.412. - - idem, different pattern, Figure (M. P. 9lh Edn., Figs. 574 — 576), with a massive horse-shoe magnet which is set into motion Cl. 4161, 2802, 2801, 2862, £ S. d. 0. 16. 0 1. 4.0 6. 0. 0 1. 0. 0 1. 10. 0 2803, 6020, 2661. 970 Voltaic Electricity. Section 6: Electro-magnetism and Electro-dynamics. No. 62413 — 62 417. 1 : 4. iii-'.li:;. Apparatus for the Rotation of a Movable Current about a Magnet, V i g u i • c (M. £ P. 9lb Edn. Ill, Fig. 579; Gan.-Man. Fig. 736; Gan.-Rein. Fig. 885) 1. i'.L'.H5. Apparatus for the Rotation of a Magnet about its own Axis under tlic Influence Current, Figure (M. P. 9th Edn. Ill, Fig. 587) of a 4.0 62,414. Apparatus for the Rotation of a Magnet about a Fixed Current, Figure (.M. I'. 9th Edn. Ill, Fig. 583) 1. 4. o 1. 4. (• Apparatus for the Rotation of a Current by the Action of another, F i nc of tin- poles (if :i vertical horse-shoe magnet (to the right of the illustration) is fitted with a wood bush having a mercury gutter into which a copper wire stirrup plunges. The mercury is connected with the one connecting terminal and the copper stirrup with the other (both shown in illustration). The other pole of the magnet (to the left) carries a zinc vessel in which is fitted a copper ring suspended on a copper stirrup. As both stirrups are pivotted the first device is set into rotation when the current passes through and the second when the zinc vessel is filled with dilute sulphuric acid. CI. IMS, MM, MM. MM, 2667. No. 624i5. Voltaic Electricity. Section 7: Induction Currents. 971 62 420. 1 : 9. 62418. 1:3. 62 419. 1 : 3. 62 422. 1 : -2. 62 423. 1 : 4. 62 424. 1 : 3. 62.419. Apparatus after Faraday, simpler, Figure A rigid wire, arranged to move in a hook, rotates about the pole of a magnet when traversed by the current, thus describing the outer surface of a cone. The current is conducted (1) by the hook-suspension, (2) by a mercury gutter into which is plunged the free movable end of the wire. 62.420. Apparatus for the Electromagnetic Action on Flexible Conductors, Figure (M. P. 9th Edn. Ill, Fig. 582) 2. 0. 0 A very flexible copper rope, loosely guided upon the elongated conical core of an electromagnet, winds itself spiral-form on the latter when traversed by a powerful current. If the current is reversed by the commutator it unwinds itself and again winds itself up in the reserve direction. 112,421. -- idem, double preceding size 4. 10.0 (12,422. Apparatus after Weinhold, Figure (W. D. Fig. 539 [512]), for the rotation of liquid conductors as showing the action of crossed currents; for the Horizontal Projection Apparatus | 0. 12. 0 £ s. d. 1. 10. 0 Section 7: Induction Currents. 62.423. Horse-shoe Magnet with Armature and Induction Coil, after Friedr. 0. G. Miillet (M. £ * d. T. Fig. 217), for proving the laws of induction <>. 12. 0 62.424. Model for explaining the Laws of Magnetic Induction for actuated conductors, Figure (W. D. Fig. 556 [529]) 0. 3. 0 The apparatus consists of three sheet iron strips soldered together at one end at right angles to each other being tapered at the other end and painted in different colours; they are marked B, E. M (Bewegungsrichtung des Leiters [Direction of Motion of the Conductor], Electromotive Force, Magnetic Field). (12.425. Automatic Induction Indicator after Pfaundler (M. P. 9th Edn. Ill, Fig. 566) ... 0. 5. 0 01. 2668, 2669, 2670, 4U5, 4679, 2654. 972 Voltaic Electricity. Section 7: Induction Currents. No. 62 426 - 63427. 1:10. 62426. 1:7. 62 429. 1 : 8. 62 430. 1 : 10. 52064. 1:7. 62.426. Apparatus for Explaining the Existence of the Magnetic Induction Current and the rule for its direction, Figure (M. P. 9th Edn. Ill, Fig. 565); Electromagnet with in- dication of lines of force and device for the presence of the induction current . . . 62.427. Simple Earth Inductor for Direct and Alternating Current, alter s/ymansky, The most suitable galvanometer to use for above is Szymansky's, No. 61,342, p. 883. 62.428. Coil for showing Induction by the Earth's Field after Weinhold (\V. I), p. 853 [791]) 62.429. Earth Inductor after Friedr. ('. (1. Miiller, F i g u r <• (M. T. Fig. 220), with 200 turns and a winding surface of 200 sq. cm 62.430. Earth Inductor after Palmieri, Figure (M. P. 9th Edn. Ill, Fig. 644), with round frame 300 mm diameter, with 100 turns of 1 mm thick wire, with commutator and slip rings for taking off D. C. and A. C. and with device for rotating the winding frame hori- x.ontally and vertically 52.064. Earth Inductor, F i g u re, \\ith commutator and slip rings for taking off 1). C. and A. C., for the Whirling Table (Frick, phys. Techn. II, 1, Fig. 1118) 52,063. -- idem, for taking off I). C. only 62.433. Iron Bar, 60 cm long, with copper wire winding (.M. P. 9th Edn. Ill, Fig. (554). for showing that an induction current occurs when a bar magnet is passed along the winding 62.434. Induction Coil F i g u re, fixed horizontally on a stand, with a powerful bar magnet, for showing the presence of an induction current when the magnet is introduced into the coil <1. 2655, 2660, 4122,6007, i s. d. 1. 12. 0 1. 10.0 0. 10.0 3. 10. 0 3. 0. 0 1. 16. 0 1. 13. 0 0. 7. 0 0. IS. 0 MM. No. 62 442. Earth Inductors, Induction Machines. 973 62 434. 1 : 6. 63 435. 1 : 10. 62 440. 1 : 4. 62 436. 1 : 6. 62442. 1 : 16. 62,435. Apparatus after Faraday, for showing the induction currents present when an electro- magnet is magnetized, F i g u r e (Kolbe-Skellon, Introduction to Electricity, Part II, Fig. 142), with two handles as electrodes »;•_>. -I'M. Magnetic Induction Machine after Stohrer, Figure (M. P. 9lh Edn. Ill, Fig. 613), for demonstrating induction phenomena, water-decomposition, incandescent light, arc light and electro-magnetism, with commutator and device to enable the two armature coils to be put in parallel or series Accessories for No. 62,436: 62,437. 2 Grips with connecting leads , . . . 62,212. U-shaped Glass Tuhe with platinum electrodes for electrolysis of water t>2,43X. Glow Lamp Stand with Edison Socket and Glow Lamp <>2,43M. Stand for clamping thin Carbon Rods, for arc light t>2.L'f>!). Horse-shoe Electromagnet with suspension ring and armature For Magnetos: see Nos. 62,358—62,361, p. 961. <»2,44o. Magneto-electric Induction Apparatus, Figure . d. 1. 8. 0 10. 0. 0 62,442. Apparatus for Experiments on Induction, after Kolbe, Figure (Kolbe-Skellon, Introduction to Electricity, Part II, Fig. 143) consisting of a 350 mm long electromagnet on wood rod, with 100 turns copper wire, and a second wire coil on base with 100 turns, ;il so two wooden gallows for same for screwing on to the Lecture Table 0. 3. 0 0. 8. 0 0. 6. 0 0. 8. 0 0. 8. 0 0. 0 2. 8. 0 ( 'I. 2679, 2680, 5539, 2681.5762. 974 Voltaic Electricity. Section 7; Induction Currents. No. 62444 — 62 444. 1 : 5. 62461. 1:4. 62 448. I : .->. 62 462. 1 : 4. 62.444. 2 Induction Coils after Weinhold, Figure (W. D. Fig. 555 [528]), for the funda- mental experiments on induction; can also be placed crosswise over each other; with bar magnet 120 mm long and 12 mm thick 62.445. - - i d e m, larger pattern «io.oo7. Cylindrical Bar Magnet for above, 150 mm long, 10 mm thick 62.447. Induction Coil (M. P. 9th Edn. Ill, Fig. 732), with two different coloured wires wound in parallel 02.448. 2 Wire Coils (M. P. 9"' Edn. Ill, Fig. 729, Gan.-Man. Fig. 773; Gan.-Rein. Fig. 966), for inserting one in the other, with bundle of iron wires as core, Figure . . . . 62.449. Cylindrical Bar Magnet for above | 62.450. Induction Coil with Interrupting Wheel, Figure | The :i|>|iar;itns consists of a largo wood reel wound with thin copper wire. The following fit into this coil: ] solid soft iron core with suspension hook which can be screwed out; I iron wire bundle for self-induction experiments; and 1 coil for mutual induction, wound with thick copper wire, into which a thinner iron wire bundle fits. In addition an interrupting wheel is supplied for physiological effeci- 02,15 i. Cylindrical Bar Magnet for above 62,437. 2 Handles for above with flexible leads 62,452. Interrupting Wheel alone, cf. Figure 62,450, to the right 62.461. 2 Wire Coils for inserting one in the other, F i g n re. the inner one wound with thick wire, with bundle of soft iron wire and with an interrupting wheel; the external coil wound with fine wire; on base 62.462. --idem, larger, Figure, mounted on wood board, with interrupting wlierl, iron wire bundle, bar magnet, and two handles for physiological purposes 62.463. 2 Induction Coils, F i g u r e, with iron bar, bar magnet, and membrane .... The primary wire coil, the magnet and the membrane are mounted on a carriage frame with rollers so that they may be conveniently introduced into the secondary coil. The apparatus can be used at the same lime for explaining the telephone. ( '1.6027, 2805, 2806. 2807. £ s. d. 0. 16.0 1. 0. 0 0. "2. I) 0. 10.0 0. IS. (I 0. 2. 0 1. Hi. I) 0. 2. 0 0. ,S. o 0. 12. 0 1. 10. 0 2. 0. 0 .">. 5. 0 No. 62469. Mutual Induction. 975 62 463. 1 : 6. 62 467. 1 : 3. 62 466. 1 : 4. 62 469. 1 : 6. 2,4<>5. Circuit-breaking Device after Buff (M. P. 9th Edn. Ill, Figs. 750—752) demonstrating; the •>2.4t>»>. Induction Coils with Magnetic Hammer Break, Figure, for fundamental phenomena of induction and of the extra current . (ii',407. Slide Induction Apparatus with Magnetic Hammer Break, Figure, for physiological purposes t)L'.4(i8. Apparatus, after Branly, for Induction Currents of the higher order If the primary current of a spark coil connected with the apparatus is opened, a current is induced in the secondary winding and traverses a spark gap and one of two spirals wound on the same ebonite cylinder. An induced current is consequently produced in the second winding on opening and closing, and ignites a gas jet and flows through a spark gap and a second inductor, as a primary current. Use is made of four spark gaps, five gas burners and three ebonite cylinders having two windings each. 62,469. Slide Induction Apparatus, after Dubois-Beymond, for all fundamental experiments on induction, Figure, with one iron core, one bar magnet and two handles . . Cl. 2808. 2811 5128. £ S. d. ; 0. 16. 0 ! 2. 0.0 2. 8.0 1. 10. 0 17.10.0 3. 10. 0 5740, 976 Voltaic Electricity. Section 7 : Induction Currents. Xd. 62470- 62470. 1:3. 62 471. 1 = 5. 62 478. 1 : fi. 62480. 1:8. 62.470. Apparatus for showing the Extra Current, after Dr. Geschbser, F i g u r e (Ztschr. t f. (1. phys. u. chem. U. 11, 1898, p. 83) 1. 1. tl 62.471. Apparatus for demonstrating the Extra Current, Figure (M. P. 9"> Edn. III. Fig. 742) 1. 12. 0 62.472. Experimental Arrangement for proving Self-induction, after Kann. with a glow lamp connected in parallel to a coil of high self-induction (Ztschr. f. d. phys. u. chein. U. 16, 1903, p. 284) 1. 10. (i Standards of Self-Induction after \Vien, Figure, constructed in accordance with the data of the Physikalisch-Teehnische KVichsanstalt (E. T. Z. 1903, p. 504). Henries 0,0001 0,001 0,01 0,1 0,5 1 Value cm 10:> 10H 107 lns 5 • 10s K)'1 List Xo. 62,473 62,474 62,475 62,476 62,477 62,478 £ 1.5.0 1.5.0 1.12.0 2.5.0 3.10.0 4.10.0 These standards arc wound on iron-free reels of serpentine stout- aud fixed so as to allow of no play. By obviating all metal parts with the except ion of the small terminals and by sub-dividing the winding the occurrence of eddy currents is prevented. The standards arc calibrated to within U.IMi-J of their value and can be, provided with certificates from the I'hysikalisch-Technische Rcichsanstall on payment of the necessary fees. 02, 479. Induction Coil for calibrating Ballistic Galvanometers, consisting of a long coil thr field density of which can he calculated from the dimensions, and a short coil slipped over the former 1. 5. 0 02,4X0. Apparatus after I'liicker and Fessel, Figure, for causing an induction current by rotating two magnets (M. I'. 9"' Fdn. III. Fig. 58 4) 1. 10. o 52,062. -- idem, for the Whirling Table. Figure on p. 2SS 1. 8.0 62,4-si. Apparatus for Unipolar Induction, alter Weber (M. I>. 9th Edn. Ill, Figs. 590 and :.'.•!) 5. o. o 62,4X2. Apparatus for showing Damping by Induction, Figure (W. I). Fig. r>:>7 |5.".o|), copper stirrup with magnetic needle swinging therein 0. is. o ti-.is.',. Apparatus for showing Damping by Induction, after Weinhold, Figure (W. l>. Fig. 558 [531 j), for the horizontal Projection Apparatus <>. is. o 02.4X4. v. Waltenhofen's Pendulum for showing the Damping Effect of Induction, F i g u r e (W. I). Fig. 559 |532|) 2.10.0 OL inis, 3708. •J8I9. 267-2. No. 62 489. Sell-Induction. Damping Action of Induction. 977 62 482. 1 : 4. 62 483. 1 : 4. 62 484. 1 : 9. 62 485. 1 : 4. 62 486. 1 : 8. MAX KOHL, CHEMNITZ 62 489. 1 : 4. 62,485. Accessories for Dia- and Paramagnetic Experiments, Figure, consisting of: 2 pole £ »• d. pieces with conical ends, 1 stand for suspending the dia- and paramagnetic bodies, a glass tube for holding off air currents, and 3 small bars of antimony, bismuth and glass . 1. 0. 0 62,486. Apparatus for showing the Damping Action of Induction, Figure A bar magnet is suspended in a glass box having levelling screws. On the bottom of the box four copper plates of different thickness and a brass plate of the same size can be laid in such manner that the distance from the magnet is always equal. The variation of damping is very striking. 52,059. Apparatus for Arago's Magnetism of Rotation, Figure on p. 287 (W. D. Fig. 560 [533]), for the Whirling Table An adjustable glass plate with magnetic needle is arranged above a large rotating copper disc. On rotating the disc the needle is deflected in the direction of rotation, it being itself finally set in rotation. :>L'.iKiO. Rotating Magnet with rotary Copper Disc placed above it, Figure, on p. 287, for the Whirling Table When the magnet is rotated the copper disc rotates in the same direction and almost as quickly as the magnet (as the armature in an asynchronous three-phase motor). 62,489. Apparatus for Generating Eddy Currents in a Copper Disc rotating between the Poles of an Electromagnet, Figure (cf. M. P. 9th Edn. Ill, Fig. 691), with stand . . . 52,061. --idem, for the Whirling Table, Figure on p. 288 The copper disc is rotated at a moderate speed without allowing the current at first to pass into .the electromagnet. As soon as the current is closed it is noticed that a considerably larger expenditure o-*. force is necessary to rotate the disc rapidly. 5. 0.0 1. 4.0 1. 0.0 3. 0.0 1. 8.0 Regarding above, cf. also Accessories to Electromagnets Nos. 62,281—62,313. Cl. 2688, 2691, 6026, 2690, 2692, 2695. go 978 Voltaic Electricity. Section 7 : Induction Currents. 62513. 1:7. 62 533. 1 : 10. Induction Coils and Accessories. Our output of Induction Coils up to the present amounts to over 3500. Our Induction Coils, which are constructed from an experience extending over many years, and which are unsurpassed in efficiency by any other make, are built of the best materials, which are submitted to the most stringent tests before being worked up. The reels are made of stout tubes with end discs and ebonite jacket and, with the exception of the very small apparatus, can be detached from the stands. The method of constructing the secondary coils ensures that each individual winding is thoroughly well insulated. In the case of sizes 7 — 15 a, types A, B, C, D and E, the Primary Coils arc enclosed in a separate ebonite tube from which they can be taken out. We supply the Induction Coils either with a base to enable them to be placed on a table, or, if desired, with Wall Bracket, the prices of both patterns being the same. For working with Wehnelt "Interrupters the coils are fitted with controllable self-induction (thus varying also the ratio of transformation and the secondary voltage attained). This regulation can either be carried out by Plugs or with a Pachytrope (Multiple Commutator). We supply our Induction Coils in the following patterns: I. Induction Coils with Normal Winding. (l) For Wehnelt Interrupters, with Condenser, viz: (a) Type A, with Multiple Commutator for varying the self induction of the primary coil. ct. I'ii: 112.533. (b) Type B, with Plug Commutation for varying the self induct ion of the primary coil, cf. Fig. 62,513. (-') For Wehnelt and Motor Interrupter, with Condenser: (a) Type C, with Multiple Commutator for varying the sell-induction ot the primary coil. cf. Fig. ti-J.fi.'iN (b) Type I), with I'lug Commutation for varying the sr]t' induct ion of the primary coil, ef. Fig. 1)2. ~1S- C\. 2831. 2835. Induction Coils. 979 62 571. 1 : 10. (3) For Motor Interrupters, with Condenser, without commutation or Primary Coil. Type E, cf. Fig. 62,571. (4) With Mercury Interrupter, with Condenser and Ruhmkorff Commutator. Type F, cf. Fig. 62,613. (5) With Platinum Interrupter, with Condenser and Ruhmkorff Commutator. Type G, cf. Fig. 62,624. (6) With Mercury and Platinum Interrupters, with Condenser and Ruhmkorff Commutator. Type H, cf. Fig. 62,636. (7) With Platinum Interrupter of special construction having very thick platinum contacts, with Condenser, Ruhmkorff Commutator and Spark Gap for Wireless Telegraphy and Rontgen Ray purposes. Coil not detachable. In carrying case. Type J, cf. Fig. 62,641. (8) With Platinum Interrupter, as before, and with Mercury Interrupter; with Condenser, Ruhmkorff Commutator and Spark Gap for Wireless Telegraphy and Rontgen Ray purposes. Coil not detachable. In carrying case. Type K. (9) With Platinum Interrupter: for Glow Lamp Factories; with Condenser, Ruhmkorff Commutator and Glow Lamp Holder. Type L, cf. Figs. 62,624 and 62,624 a. II. Rontgen Ray Induction Coils, with low -resistance Secondary Winding, specially for Rapid Radiographic Work, and for Charging Condensers. (MM For Wehnelt Interrupters, without Condenser, viz: (a) Type R J A, with Multiple Commutator for varying the self-induction of the primary coil. (b) Type R .1 B. with Plug Commutation for varying the self-induction of the primary coil. (11) For Wehnelt and Motor Interrupters, with Condenser: (a) Type R J C, with Multiple Commutator for varying the self-induction of the primary coil. (b) Type R JD, with Plug Commutation for varying the self-induction of the primary coil. (12) For Motor Interrupters, with Condenser, without Commutation of Primary Coil Type R J E. The induction coils with Wehnelt and Motor Interrupters are worked as a rule with Direct Current from heavy current mains. The most useful voltage for hoth types of interrupter and for coils having a spark length of over 300 mm, is 110. Induction coils of below 300 mm spark-length work better with a pressure of 65 volts when Wehnelt Interrupters are used. The Motor Interrupter yields good results with the considerably lower voltage, and can also be worked with cells or accumu- lators. The minimum voltages necessary for the same are the following; which also hold good for mercury and platinum interrupters: I'p to 200 mm spark-length 12 volts 350 400 450 500 600 16 24 32 48 64 The current consumption for the maximum spark-length is, for Motor Interrupters, about 3 — 5 amps.: for Welmelt Interrupters with spark -lengths to 300 mm, approx. 30 amps.; above 300, approx. 20 — 25 amps. With pressures above 130 volts shunt resistances are absolutely necessary, and when possible they should be used when employing Motor Interrupters. When ordering, kindly give particulars as to kind of current and voltage. A test certificate and directions for using are appended to each Induction Coil. If desired, and at an extra cost of 5 per cent, we fit all our Induction Coils with suitable mica insulation for hot coun- tries; this prevents deformation taking place in the insulating material. CJ. 28S7. 62* 980 Voltaic Electricity. Section 7: Induction Currents. No. 62 491 — 62 636. 1 : 6. 62 607. 1 : 8. Induction Coils without Interrupter, Type A, B, C, D and E, on Table Stand. Spark- length with Wehnelt - Inter- rupter Size For Wehnelt Interrupter For Wehnelt and Motor Interrupters For Motor Interrupters Spark- length with the Motor Inter- rupter Type A WithoutCond enser, Primary Coil with Pachytrope, cf. Pig. 62533 Type B WithoutCondenser, Primary Coil with PlugCommutation, cf. Fig. 62513 Type C With Condenser, Primary Coil with Pachvtrope, cf. Fig". 62533 Type D With Condenser, Primary Coil with PlugCommutation, cf. Fig. 62513 Type E With Condenser, Primary Coil without Commutation, cf. Fig. 62571 nun List No. £ s. d. LhtNo. £ s. d.|[ListNo. £ s. d. List No. £ s. d. List No. £ s. d. mm I. Standard Secondary Winding. 2 — — — — ^ — — — — 62559 8. 0.0 90 — , 3 — — . — — — — — — 62560 10. 0.0 120 4 — — — — — — — — 62561 12. 0.0 150 250 5 62491 16.10.0 62508 15.10.0 62525 18.10.0 62542 17.10.0 62562 15. 0.0 200 300 6 62492 20. 0.0 62509 19. 0.0 62526 22. 0.0 62543 21. 0.0 62563 18,10.0 250 350 7a 62493 26. 0.0 62510 25. 0.0 62527 28.10.0 62544 27.10.0 62564 25. 0.0 300 350 7b 62494 30. 0.0 62511 26. 0.0 62528 32.10.0 62545 28.10.0 — — 300 400 8 62495 37. 0.0 62512 33. 0.0 62529 39.10.0 62546 35.10.0 62566 32.10.0 350 450 9 62496 44. 0.0 62513 40. 0.0 62530 47. 0.0 62547 43. 0.0 62567 40. 0.0 400 500 10 62497 54. 0.0 62514 50. 0.0 62531 57. 0.0 62548 53. 0.0 62568 50. 0.0 450 550 11 62498 65. 0.0 62515 60. 0.0 62532 68.10.0 62549 63.10.0 62569 60. 0.0 500 600 11 a 62499 75. 0.0 62516 70. 0.0 62533 78.10.0 62550 73.10.0 62570 70. 0.0 566 650 12 62500 85. 0.0 62517 80. 0.0 62534 88.10.0 62551 83.10.0 62571 80. 0.0 600 700 12 a 62501 95. 0.0 62518 90. 0.0 62535 99. 0.0 62552 94. 0.0 62572 90. 0.0 650 750 13 62502 105. 0.0 62519 100. 0.0 62536 109. 0.0 62553 104. 0.0 62573 100. 0.0 700 800 13 a 62503 115. 0.0 62520 110. 0.0 62537 119. 0.0 62554 114. 0.0 62574 110. 0.0 7.-.i» 850 14 62504 125. 0.0 62521 120. 0.0 62538 129. 0.0 62555 124. 0.0 62575 120. 0.0 800 900 i 14a 62505 135. 0.0 62522 130. 0.0 62539 140. 0.0 62556 135. 0.0 62576 130. 0.0 900 950 15 62506 150. 0.0 62523 145. 0.0 62540 155. 0. 0 62 557 150. 0.0 62577 145. 0.0 950 1000 1 15 a 62507 165. 0.0 62524 160. 0.0 62541 170. 0.0 62558 165. 0.0 62578 160. 0.0 1000 II. Low Resistance Secondary Winding. .H50 RJI 62579 34.0.062581 30.0.062583 36.10.062585 32.10.062587 400 RJII 62580 41.10.062582 37.10.062584 44.0.062586 40.0.062588 29.10.0 350 37. 0.0 400 Sizes 5 — 7a for Wehnelt Interrupters have double, 7b — 10, quadruple, and 11 — 15 :i, sextuple commutation of the I'rimiiry Coil. £ s. . Small Induction Coils, simple pattern, Figure, with Platinum Interrupter, without Commit- £ * (1 tator, on polished mahogany box, coil of wood, not detachable List No. 62,652 62,653 62,654 62,655 62,656 Spark -length mm 6 10 15 20 30 £ 0.10.0 0.15.0 1.13.0 2.0.0 2.10.0 — i d e m, with simple Commutator. List No. 62,657 62,658 62,659 62,660 Spark-length mm 12 15 20 30 £ 1.0.0 1.18.0 2.5.0 2.15.0 62,661. Induction Coil, for demonstration purposes, can be taken to pieces, Figure, with adjustable secondary coil and Condenser which can he drawn out; spark-length 40 mm 6. u. 0 Carrying Cases for Induction Coils. List No. 62,662 62,663 62,664 62,665 For Size 0000 — 0 1—5 6—8 9—11 £ 1.5.0 1.10.0 1.15.0 2.10.0 Interrupters. (a) Electrolytic Interrupters for Direct and Alternating Current. The Electrolytic Interrupters are charged with dilute sulphuric acid (if 1,06 to 1.12 sp. gr. i'nr prices of Wehnelt Interrupters arc liable to alteration without notice on account of the fluc- tuations in the price of platinum. 62.666. Wehnelt Interrupter for Direct Current with 1 platinum pin 1 nun thick, with large glass vessel, Figure, with conical porcelain tube ............... 3. Id. u 02.667. Wehnelt Interrupter for Direct Current, with 3 platinum pins l mm thick, with large glass vessel .................................. 6.16.0 62.668. Wehnelt Interrupter with 1 platinum pin 3 mm thick, for working with Alternating Current, ef. Figure 62,666 .......................... :». Id. 0 It is possible to work with Alternat mi; Current but this cannot l>e recommended as the platinum pin is rapidly consumed and regulation difficult. The primary coil also must lie specially ••tuned". 5345, 2850. No. 62673. Small Induction Coils. Interrupters. 983 ^s^^m- 62 670. 1 : 4. 62 672. 1 : 4. 62 673. 1 : 5. (b) Motor Mercury Interrupters for Direct Current. £ a. d. We supply the following Motor Interrupters for pressures of 16, 24, 32, 65, 110, 150 and 220 Volts and would ask that the voltage desired be stated when ordering. If this is not given we supply the Interrupters for 110 volts. The price of all Interrupters is exclusive of the mercury necessary for charging. 62.669. Motor Mercury Interrupter (Kohl's pattern) with immersion contact, without tachometer 7. 15. 0 62.670. -- idem, with tachometer, Figure ; 11.15.0 62.671. - - idem, without switch or commutator 7. o.'O 62.672. Motor Mercury Interrupter with Immersion Contact (Kohl's design), light pattern, Figure 5. 0. 0 62.673. Centrifugal Mercury Interrupter, F i g u r e, including mercury charge, for Direct Current pressures of 32, 110, or 220 volts 9. 0.0 In this Interrupter the mercury is successively centrifvigated during rotation, thus preventing enmlsionising. In this manner a regular, certain contact is assured as well as great certainty in action, and constant cleaning and recharging, necessary with other mercury interrupters, is but seldom required. The number of interruptions can be regulated within wide limits. <-l. 2856, 2S62, 845?. 984 Voltaic Electricity. Section 7: Induction Currents. No. 62674 — 62 674. 1 : 6. 62 676. 1 : 4. 62 679. 1 : 5. 62 681. 1 : 5. 62 682. 1 : 6. 62.674. Mercury Jet Interrupter, without tachometer, Figure (cf. Gan.-Eein. Fig. 1030) Charge: 8000 g mercury and 1500 g petroleum. 62.675. - - idem, with tachometer 62.676. Turbine Interrupter, without tachometer, Figure The Interrupter is filled with 2000 g (150 ccm) mercury and 1250g (1400 com) alcohol of at Vast 8,3 "„. 62.677. — idem, with tachometer . . .- 62.678. Contact Ring for the Turbine Interrupter with different number of hollows .... 62.679. Turbine Interrupter, simpler, Figure Charge 1250 g mercury and 1000 g (1120 ccm) alcohol. £ s. d. 9. 0.0 14. 0. 0 10. 0.0 15. 0.0 . 0.15.0 6. 0.0 1. 0.0 62.680. Regulating Resistance for the Motors of the Direct Current Interrupters . . . (c) Motor Mercury Interrupters for Alternating Current. 62.681. Turbine Interrupter for Alternating Current, Figure, with synchronism indicator; also suitiihlr for charging accumulators 16. 111. 0 The exact frequency and volta^r should be given when ordering. We have a special price list dealing with Switchboards and Resistances for working Induction Coils, especially those used for X-Ray purposes; we shall be pleased to send this on appli- cation. (I. 2857, 28S8, 2858, 2863, 2873. No. 62 702. Interrupter, Sparking Pillars, X-Ray Tubes. 985 62 699. 1 : 5. 62 683. 1 : 8. 62 691. 1 : 4. 62 685. 1 : 5. Sparking Pillars and X-Ray Tubes. 62.682. Sparking Pillars for spark-lengths to 200 mm, Figure 02.683. - - idem, for spark-lengths to 450 mm, Figure. . 62.684. - - i (I e m, for spark-lengths to 1000 mm 62,685. Sparking Pillars, Figure, with joints so as to be able to set the spark gap hori- zontally and vertically, for metallic spectra, for spark-lengths to 450 mm X-Ray Tubes, for small load, for working in connection with Induction Coils having platinum, mercury and motor interrupters, also with influence machines, Figure, with osmose regeneration. List No. 62,687 62,688 62,689 62,690 62,691 62,692 62,693 62,694 62,695 Spark-length to mm 100 120 200 300 400 500 600 700 800 £ 0.14.00.17.00.18.61.0.0 1.2.3 1.4.6 1.6.6 1.8.61.10.6 X-Ray Tubes, with massive anticathode, for heavy loads and for working with Wehnelt or Motor Interrupters, with regeneration by osmose, Figure 62,702 700 mm 2. 13. 6 List No. 62,697 62,698 62,699 62,700 62,701 Spark-length to 200 300 400 500 600 £ 1.10.0 1.14.6 1.19.0 2.3.6 2.8.0 As the vacuum of the X-Ray Tubes intensifies by use they must be fitted with a so-called regene- rating device if the life has to be prolonged to any extent. The tubes have osmose regeneration; this is based on the property possessed by palladium to be permeable to hydrogen when in the incandescent state. The device consists of a small palladium tube fused in. When the vacuum in the tube has become too high, i. e. when the tube has become hard, the end of the small palladium tube is made red-hot for a few seconds by means of a spirit lamp, without the flame being allowed to come into contact with the fused part of the glass. Hydrogen is diffused into the tube from the core of the flame through the incandescent palladium tube and the vacuum is lowered, i. e. the tube is rendered softer. The tube should be allowed to cool thoroughly before being used again. X-Ray Tubes for Medical Purposes supplied in all patterns - - see special list. Cl. 5409, 12 1-, 2882, 2874. £ s. d. 1. 0.0 1.16.0 2.10.0 2.14.0 986 Voltaic Electricity. Section 7: Induction Currents. Xo. 62 704 — 51 110. 1 : 8. 62 705. 1 : 6. 62 721. 1 : 8. 51,110. Simple Wood Stand for holding X-Ray Tubes, Figure. Price without Tube £ illustrated 0. 62.704. Milliammeter for High Tension Currents; base-diameter approximately 120 mm; for measuring the current flowing into the X-Eay Tube; Weston type instrument with range to 5 milliamperes, on serpentine base 3. Hi. o 62.705. - - i d e m, with two ranges (to 5 and 50 milliamperes), Figure 4. :>. 0 Fluorescent Screens coated with Barium platinocyanide, excellent in action, in wood frame. The Barium platinocyanide Screens are covered with a slab of stout lead-baryta glass which protects the observer from the action of the Bontgen Bays but allows the image to appear without any change. List No. 62,706 62,707 62,708 62,709 62,710 62,711 Size cm 9x12 13x18 18x24 24x30 30x40 40x50 £ 0.17.0 1.10.0 2.7.0 3.13.0 6.0.0 9.13.0 If provided with handles and protecting sheets, the price of each screen is increased by £ 0. s. o. The prices of all Fluorescent Screens are liable to change without notice owing to the fluctuations in the price of platinum. Fluorescent Screens coated with Barium platinocyanide, very efficient, in wood frame, without protective lead glass. List No. 62,712 62,713 62,714 62,715 62,716 62,717 Size cm 9x12 13x18 18x24 24x30 30x40 40x50 £ 0.14.0 1.6.0 2.2.0 3.6.0 5.11.0 9.0.0 Cryptoscopes, Figure, with Fluorescent Screen which can be List No. 62,718 62,719 62,720 Size of Fluorescent Screen cm ... 9x12 13x18 18x24 (a) Without Lead Shielding Glass . £ 1. 4. 0 1. 17. 0 2. 15. 0 (b) With Lead Shielding Glass ... £ 1. 7. 0 2. 1. 0 3. 0. 0 withdrawn. 62,721 62,722 24x30 30X40 4. 1. 0 6. 16. 0 4. 8. 0 7. 5. 0 - idem, without Fluorescent Screen List No. 62,724 62,725 62,726 62,727 62,728 For Fluorescent Screen cm 9 X 12 13 X 18 18 X 24 24 x 30 30 X 40 € 0. 10. 0 0. 11. 0 0. 13. 0 0. 16. 0 1. 5. 0 By using the Cryptoscopes radioscopy can be carried on without darkening the room 62,723 40x50 10. 5. 0 10. 18. 0 62,729 40 > .")() 1. 10. 0 62.730. Cardboard with Strips of different Metals, for checking the penetrative power of X-Rays 0. in. o 62.731. Apparatus for Demonstrating that the Air is Ionised by X-Rays. Price without X-Ray tube or electrometer, but with bellows 2. 0. 0 The apparatus consists of a wood box (lined with sheet lead) which encloses one of the X-Ray tubes NIIS. (32,687 — 62,691 or 62,697 — 62,699. The \-Kays issue out of an aperture placed opposite the anti- cathode and discharge an electroscope opposite. If the electrometer is set up somewhat laterally ii ran also be discharged if the ionised air is deflected on to it by the bellows. A suitable electrometer to use is liraun's. No. (iO.21 1 — 60,215, p. Sil.'t. or Kolhc's No. till. 1!M>. p. 8M:>. It is advisable, however, to place a plate of large surface on the electrometer. (iL'.732. Plate for plariiig on the Kleet rometer ( Bnmn's or Kolbe's) 0. 2. 0 See complete special list for further Accessories for Rontgen Ray Investigations. This is sent on receipt of a card. CL i . 5635, 288«. N.I. Ii2737. Dynamos. Explanatory Models. 987 62 734. 1 : 7. 62 735. 1 : 0. 62733. 1:8. 62737. 1:12. Dynamos. Explanatory Models. 62.733. Apparatus for Explaining the Magnetic Induction of Magneto Electric Machines and £ s. d. for explaining the Pacinotti and Gramme Rings, Figure. Stand with two fixed wire coils and two rotary semi-circular magnets (M. P. 9th Edn. Ill, Fig. 649) 2. 8. 0 62.734. Model of a Pacinotti-Gramme Machine, after Pfaundler, Figure 5. 0. 0 The Model can be worked, can be used as a series or shunt motor, and, used as a dynamo, gives a current which can be shown by a vertical galvanometer. If the magnets are excited by a separate source of electricity the current generated is strong enough to work a bell. 62.735. Model of a Pacinotti-Gramme Machine, Figure (W. D. Fig. 565 [538]), with ring armature arranged very comprehensively. The machine can be used to generate a current, also to rotate under the influence of a current 2. 15. 0 52,067. Model of a Pacinotti-Gramme Machine, after Pfaundler, F i g u r e, on p. 288 (M. P. !»"' Kdn. Ill, Figs. 659 and 660), for the Whirling Table, with device tor demonstrating the lines of force 6. 10. 0 The following pertain to the apparatus: an iron armature, wound; an iron armature, unwound; a wood armature with winding and a frame stretched with paper for demonstrating the lines of force. 62,737. Model of a Magneto Electric Machine, Figure, after Friedr. C. G. Miiller (M. T. Figs. 227 — 230), with one each wound Siemens H Armature, ring armature, drum armature and an unwound drum- armature . 4. 4.0 Cl. 2691). f.Hii, 2697, 4511. 988 Dynamos. Explanatory Models. No. 62 738 — 62738. 1:10. 62.738. Magnet Stand and Movable Armature Coil, Figure, for explaining the dynamo- electric induction in dynamos, after Gb'tze, with a wood rail, and an iron rail to serve as track or core of the movable coil 52,066. Apparatus for explaining the Magneto-electric and Dynamo-electric Principle, for the Whirling Table, Figures A and B on p. 288 The apparatus consists of: 1 Pacinotti Ring, 1 Magnet, 1 Electromagnet, 1 Brush Conductor. 62.739. -- idem, without magnet, as effective model of a dynamo, for placing on the Whirling Table 62.741. Model of a Direct Current Dynamo; can also be used as a Direct Current Motor, Figure, for explaining the machine and the most usual methods of connection and adaptations ; with a ring armature and a drum armature which can be easily interchanged The Machine can be used either as a series or shunt dynamo; when connected in shunt it can also be worked with separate excitation. In addition it works as a series or shunt motor and it is possible to demonstrate with it the action of the shunt regulator. Given in are one ring armature and one drum arma- ture, which can be easily interchanged. All windings are composed of as few turns as possible so as to increase the comprehensiveness; the individual armature coils are wound alternately with two different coloured wires to facilitate the explanation of the machine. The current obtained when driven by hand can be shown by a galvanometer and a small glow lamp. Used as a motor the machine actuates the fly- wheel together with the handle. If the machine is worked more rapidly by means of a driving frame its output is correspondingly larger. 62.742. Sliding Resistance, for use as Shunt Eegulator £ s. d. 9. 0.0 3. 0.0 •2. 5.0 9. 0.0 Apparatus after Grimsehl for explaining the Dynamo (Ztsohr. f. d. phys. u. diem. U. 6, 1893, p. 240), comprising: 62,743. Electromagnet with horizontal cores and iron frame (Fig. 1) 62,744. Current Conductor for above, showing the presence of the electric current when the lines of force intersect, for rectilinear motion (Fig.2) 62.745. — idem, for rotary motion (Fig. 3) , 62.746. -- idem, rectangular form, without commutator (Fig. 4) 62.747. - - i d e m, rectangular form, with commutator (Fig. 6) . , 62.748. -- idem, with a number of wire turns (Fig. 7) . . . . , 62.749. Siemens H-Armature (Fig. 8) , 1. 0. o 7. 0.0 0. 10. 0 0. 8.0 0.11.0 0.15.0 0. 19. 0 0.19.0 CI. 413fl No. 62 756. Dynamos. Explanatory Models. 989 62 741. 1 : 5. 62 753. 1 : 4. 62 754. 1 : 12. 62 755 A. l ; in. 62 755 B. 1:20. 62.750. Iron Ring with a group of wire turns and commutator for explaining the £ s. d. • Gramme Eing 1.12.0 62.751. Gramme Ring with 12 groups of turns and commutator in 12 parts .... 2. 2. 0 62.752. 3 Drawings for explaining Nos. 62,750 and 62,751, on cardboard 0. 3. 0 62.753. Model of a Dynamo with Gramme Ring, Figure, constructed of wood and metal; cannot be worked; for explaining construction only 1.10.0 62.754. Apparatus for explaining the Direct Current Machine having Ring Armature, after Pfaundler, Figure, very large model of wood and pasteboard; cannot be worked 2. 0.0 62.755. Apparatus for Demonstrating the Passage of the Current in the Gramme Ring when Direct, Alternating or Three-phase Current is taken off; after Hammerl, Figures A and B (Ztschr. f. d. phys. u. chein. V. 9, p. 33), with 10 discs; cannot be worked . 4. 0. 0 The apparatus consists of a firmly fixed round glass disc having an axis in the centre for a movable glass disc of the same size. Pasteboard discs with a drawing ot the Gramme Ring can be placed on the latter disc corresponding to the various cases. The windings and commutator segments are cut out and transparent coloured silk paper is pasted on behind, so that by using a black pasteboard disc cut out in lines, ;md covering the fixed glass disc, luminous points occur (by illuminating by means of a powerful source of light set up behind the apparatus) which are displaced when the movable disc is rotated and in this manner render visible the course of the currents. Fig. A shows the apparatus set up with a pasteboard disc, while the remaining 9 pasteboard discs are illustrated in Fig. B. Cl. 3817, 2704, 2795, 2706, 2707 990 Dynamos. Explanatory Models. No. 62 756 — 62 756 A. 1:11. 62756B. 1:11. 62757. 1:10. 62758. 1:8. 62 759. 1 : 4. 62.756. 4 Mechanically Movable Plates for illustrating Dynamos and Motors, after ( . Kreyer, £ s. d. Figures A and B 1.10.0 The following demonstrations can be carried out with these plates: (1) Magneto -electric Machine with double T armature (Alternating Current); (2) idem (Direct Current); (3) Dynamo with double T arma- ture; (4) Dynamo with Gramme Ring; (5) Electric Motor (Direct Current) with double T armature; (6) Electric Motor with Gramme Ring; (7) Alternating Current Machine; (8) Alternating Current .Motor (three-phase motor). To Plate I (double plate), which is suitable for demonstrations Nos. 1 — 6, the following accessories , are supplied: 1 folding disc for dynamo, 1 ditto for motor, 2 disc* for Gramme Ring, 1 coloured disc for the magnetic field, 1 commutator in two parts, and 1 ditto in 8 parts, 2 brushes. 4 connerting loads. Plate II is used for Demonstration No. 7, Plate III for Demonstration No. 8. 62.757. Model Of a Gramme Ring, F i g u r •• (W. D. p. 883 [818]), of pasteboard, 50 cm dia- meter, divided, the path of current and the poles are given 0.16.0 In the illustration one half of the ring is turned round: the poles of -iiiiil.il name go together. 62.758. Model of a Schuckert Flat Ring, with winding, Figure, with ring, commutator. and axis of wood 1. u. 0 •i-,7.~)!(. Model of a Siemens Armature, with winding, of wood. Figure til'. 7<;o. Model of a Gramme Ring Armature, same construction .... 1. o. 1. 0.0 «'l. '2708, 2708a, '.'709. 2711, 3818. Dynamos. Explanatory Models. 991 62761. 1:4. 62 762. 1 : 3. 62 762 a. 1:9. 62 763. 1 : 8. '• 62 766 a. 1:4. til'. 7(11. Model of a Drum Armature, same construction as preceding, Figure 62,762. Model of a Drum Armature, after Weinhold, Figure (W. D. Fig. 572 [545]), very comprehensive, for demonstrating the mode of winding and current action, rotating, and generating current, with magnet 62, 762 a. Model of a Drum Armature, after Weinhold, of pasteboard, Figure (W. D. p. 889 [827]) 62.763. Iron Ring for making a Ring Armature Winding, Figure, after Friedr. C. G. Miiller (M. T. Fig. 226) 62.764. - - i d e in, with winding 62.765. Winding Formers, after Friedr. C. G. Miiller, for making a drum armature winding (M. T. Fig. 229), of cardboard. Price per 10 62.766. - - idem, for ring armature winding (M. T. Fig. 225). Price per 10 »>2. 766 a. Closed Iron Ring with 2 sliding coils, after Friedr. C. G. Miiller (M. T. Fig. 216), for induction experiments and as transformer model £ s. d. 1. 0.0 3. 10. 0 1. 5.0 0. 1.8 0. 4.0 0. 3.0 0. 3.0 1. 4.0 C'l. 2712, 2710, 4139, 2715,4521. 992 Dynamos for Generating Direct, Alternating and Three-phase Current; also Accessories. NO. 62 76- Dynamos for Generating Direct, Alternating and Three-phase Current; also Accessories. 62767. 1:8. 62777. 1:12. 62,767. Direct Current Dynamo, Figure, with crossed armature and commutator in four £ * <'• sections, driving frame on polished wood board, with compound gearing, for turning by hand 3. !.">. n 62,768. Machine alone, can also be used as Motor The Machine is constructed as a shunt dynamo; it gives 15 volts und 2 amps., feeds 2 — 3 small glow- lamps or self-regulating arc lamp No. 62,815. It is possible to fuse a steel wire 0,15 mm thick and 8cm long. 2.10. (I Shunt Dynamos for Direct Current, cf. Fig. 62,774; also constructed as Universal Dynamos, with 4 slip rings, for Direct, Alternating and Three-phase Current, with Drum Armature (cf. Gan.-Man. Fig. 806). Appro: out Volts . D. C. put Amps. Approx. r. p. in. Sinfrle- phase A. C. voltage approx. volts Three- phase pres- sure ap- prox. volts Ap- prox. power re- quired HP M..-lts i W Length mm i Steel re Diam. mm Fee Glow ] No. (Is ,;llnps Hefner C.P. Feeds Arc Lamp No. Wil Drivimr rf. Fiir. l.i.-t No. lOllt Stand. 62774 £ «. •!. With Driving Stand, of. FiL's. D2777 and 627SL1 List No. £ s. d. (a) For Direct Current only. 20 3 3000 0,25 120 0,15 4 3 tii-' sir. 62770 4.10.0 62777 6. 0.0 35 4 2800 — — 0,33 250 0,2 5 8 62816 62771 8. 0.0 62778 10. 0.0 50 4 2200 — — 0,5 300 0,2 5 12 62816 62772 10. 0.0 62779 12.10.0 65 5 2200 — 0,8 400 0,3 7 16 Ill's Hi 62773 12.10.0 62780* 22.10.0 (b) For Direct Current, Monophase A. C., Three-phase Current and Dissymmetrical Two-phase A. C. 20 3 3000 14 11> 0,26 120 0,1 f) 4 3 62815 62774 5.15.0 62781 7. 5.0 35 4 2800 24 20 0,33 250 0,2 5 8 62816 62775 9. 5.0 62782 11. 5.0 50 4 2200 34 30 0,5 300 0,2 5 12 62816 62776 11.10.0 62783 14. 0.0 65 5 2200 44 38 0,8 400 0,3 7 16 62816 62 776 a 14. 0.0 62783a« 24. 0.0 The Machines are of the two-fold I.\|M. provided with Drum Armature and are also suitable for continuous * Tne Driving Stand for Nos. 62,780 and 62,783 a is constructed in accordance with Fig. 62.783 b. CI- 6045- 6046- No. 62783a. Dynamos, etc. 993 62782. 1:8. 62 783 b. 1:12. 62774a. 1:12. wpiking. They can also be used as D. C. Motors. Nos. 62744 — 62 776 a and 62,781 to 62,783 a each have four slip rings to which the corresponding points of the armature winding are connected and can also be used for converting Direct Current into Alternating or Three-phase Current by allowing them to run as electric motors and taking off Alternating or Three-phase Current at the corresponding terminals. With Machines Nos. 62,770/3 it is possible to drive, at the corresponding voltages, the D. C. Motors Nos. 62,768 and 62,834 (which should in this case be ordered for the proper D. C. voltage); and with Nos. 62,774/6 a the 2-phase A. C. Motors Nos. 62,909/14 and the 3-phase Motors Nos. 62,906, 62,907 and 62,912 (of. the precise details in the list of Motors referred to). With the A. C. transformer No. 62,967 or 62,968 and the 3-phase transformer No. 62,974 or 62,975 respectively the voltage can be increased and this transformation shown by glow lamps. For this purpose use is made of the lamp stands Nos. 62,797, 62,802 and 62,803 respectively. With each Machine are supplied four metal blocks and four screws by the aid of which the dynamos are screwed on to the lecture table. The blocks are let into the wood by a joiner. A pamphlet describing experiments is supplied with the Machine. It is well to mention here that hand drive with the driving stand is a somewhat tiring operation being only adapted for short experiments. The driving stand for Nos. 62,780 and 62,783 a is driven by two persons (cf.Pig. 62,783 b). Larger Dynamos for Power: see Vol. I of this Price List, p. 147. Cl. 2749, 6015, 2750, 4953. 63 994 Voltaic Electricity. Section 7: Induction Currents. No. 62 784 — 62737. 1:4. 62790. 1:12. 62 797. 1 : 5. 62796. 1:1-2. 62 799. 1 : 5. Direct Current Shunt Dynamos; also constructed as Universal Dynamos, with four slip rings, for Direct, Alternating and Three-phase Current, round pattern, with ball bearings, cf. Fig. 62,787. 3- Approx. D. C. effeciency Approx. revs per A. C. pressure approx. phase Pres- sure ap- Power re- quired Melts a steel wire Feeds Glow Lamps Feeds Arc Lamp Without Driving Stand, cf. Fig. 62787 With Driving Stand. cf. Fig. 62790 Volts Amps. min. Volts prox. Volts HP. Length mm Diam. mm No. C. P. No. List No. £. s. d. List NIL £. s. d. a) For Direct Current only. 10 10 2500 0.3 160 0.4 4 8 02S15 62784 7.10.0 62790 9.10.0 15 10 2200 0.4 250 0.4 6 8 62815 62785 9. 0.0 62791 11.10.0 20 11 2200 0.5 400 0.4 7 10 62816 62786 10.10.0 62792 13. 0.0 b) For Direct, Mono-phase Alternating, 3-Phase and unsyrametrical 2-phase Alternating Current. 10 15 20 10 10 11 2500 2200 2200 7 10 14 9 12 0.3 0.4 0.5 150 250 400 0.4 0.4 0.4 6 7 8 8 10 62815 62787 9.10.0 62793 62815 62788 11. 0.0 62794 62816 62789 12.10.0 62795 The remarks under Nos. 62,770 — 62,783 a apply here also in a general sense. 11. 10. 0 13. 10. 0 15. 0.0 £ s. d. 62,7!»(i. Dynamo for Direct Current, with Drum Armature, Figure, with chain drive, for rotation by one or two persons; output 20 volts, 4 amps.; crankshaft running in ball bearings 15. 0. 0 Driving Motors for Dynamos with Board (cf. Fig. 62,774 a, p. 993), quoted for on application: kindly send precise data as to current conditions. Cl. 6048, 6047, 2755, 2753, 2757 No. 62 807. Dynamos. Electric Lighting. 995 MAX KOHL CHEMNITZ 62 802. 1 : 5. 62807. 1:4. 62 806. 1 : 6. Electric Lighting and Power Transmission. Glow Lamps and Arc Lamps. 62.797. Glow Lamp Stand with small Edison Socket and Glow Lamp, from 2 — 65 volts, Figure, on serpentine stone base with ebonite pillar Unless otherwise stated we supply a 20-volt lamp. 62.798. Glow Lamp with small Edison Screw, 2 — 65 volts Glow Lamp Stands, Figure: List No. 62,799 62,800 With 3 4 £ 0.16.0 1.0.0 62,801 6 Glow Lamps 1.8.0 We supply the Lamps in voltages suiting those of the machines just listed (10, 15, 20, 35, 50 and 65 volts): kindly quote pressure when ordering. Unless this is stated we supply 20-volt lamps. Glow Lamp Stands with Plugging Device to enable the Lamps to be put in parallel and series, F i g u r e : List No. 62,802 With 4 £ 1.12.0 62,803 6 Glow Lamps 2.4.0 £. s. d. 0. 6.0 0. 1.0 As regards the Lamps, vide remarks under No. 62799. 62.804. Osram Metal-filament Glow-Lamps with small Edison screw, for pressures from 2—8 volts 62.805. - - idem, for 10—20 volts 62.806. Electric Glow Lamp in the various stages of manufacture, Figure, in case . . 62.807. Demonstration Nernst Lamp after Grimsehl (Ztschr. f. d. phys. u. chem. U. 16, 1903, p. 263), Figure, for connecting to 110 — 220 volts Direct Current The individual parts of a Nernst Lamp are arranged on one serpentine (ophite) slab in such manner as to enable the action of the same and the path of the current to be followed quite well. The voltage desired should be quoted when ordering; otherwise a 110 volt lamp is supplied. Cl. 2760, 3550, 3549. 0. 1.6 0. 2.0 1.10.0 1.10.0 63* 996 Voltaic Electricity. Section 7: Induction Currents. No. 62808 — 62808. 1:8. 62809. 1:5. 62810. 1:4. 62 816. 1 : 4. 62820, 62821. 1:5. 62.808. Glow Lamp Filament in Receiver, after Hartl, Figure, for showing that the carbon filament does not burn up in vacua but that it does in air (Ztschr. f. d. phys. u. chem. U. 10, 1897, p. 235) 62.809. Carbon Filament Lamp after Grimsehl, Figure (Abhandlungen z. Didaktik u. Philo- sophic d. Naturwissenschaft, Nr. 1, Fig. 3; published by J. Springer, Berlin, 1904) . 62.810. Glow Lamp Model after Grimsehl, Figure (Ibid., Fig. 4) Steel Wire for Glowing Experiments: List No. 62,811 62,812 62,813 62,814 Diameter mm 0.15 0.2 0.3 0.4 1 Small Coil £ 0.0.7 0.0.7 0.0.7 0.0.7 62.815. Small Arc Lamp, cf. Fig. 62,816, self -regulating, with reflector; can be worked by Dynamo No. 62,767 62.816. Arc Lamp, larger, Figure, with reflector, suitable for Machines Nos. 62,771 to 62,783 a, also 62,786 and 62,789 62.817. Carbon Rods for above Per metre 62.818. Contac 'Lamp after Eeynier, with fine carbon rod for sliding on carbon roller . . 62.819. Carbon Rods for above Per metre 62.820. Jablochkofi's Candle (Gan.-Man., Fig. 836), Figure 62.821. Holder with Terminals for above, Figure 62.822. Carbon Terminals after Briisch, Figure, without the Bunsen Stand figured, but inclusive of 2 carbon rods for 10 — 20 amps., cf. Fig. No. 62,131 Carbon Rods for above for 10 — 20 amps per pair £. s. d. 1. 6.0 0. 18. 0 0. 8.0 2. 0.0 2. 10. 0 0. 0.6 1.10.0 0. 0.6 0. 1.0 0. 8.0 1.12.0 0. 0.5 (I. 4147, 5925, 5926, 2766, 5291. 6016. No. 02 884. Electric Lighting. Motors. 997 62 838. 1 : o. 62 838 A. 1:5. 62 854. 1 : 6. Electric Motors. Cf. also Nos. 62,317—62,322 and 62,768. 62,823. Small D. C. Electric Motor, Figure, with double T-armature 62.830. Direct Current Motor, Figure, Vi2th H. P., for 12 volts, series wound and with ring armature; speed 1200 r. p. m. (approx.) at full load This motor is very well adapted for demonstrations owing to its compact construction. 62.831. --idem, for 110 volts 62.832. --idem, for 220 volts Direct Current Motors, Figures, with Drum Armatures. £ s. d. 0. 12. 0 4. 0. 0 4. 10. 0 5. 0. 0 Series Wound for 110 Volte Series Wound for 220 Volts Shunt Wound for 110 Volts Shunt Wound for 220 Volts Starting and Regulating Resistance Extra Extra Out Price con- V7UI- put: Ap- R. P. M. Price con- structed with ver- structed with tall Base, prox. (approx.) tical Axis- with Starter built H. P. List No. £. s. d. List No. £. s. d. List No. £. s. d. List No. £. s. d. List No. £. s. d. see Fig 62 838 B in cf. Fig. 62 838 A Vso 1400 62 833 1. 10. 062 839 1. 15. 0 11 /to 1500 62834 2. 0.062840 2. 5.0 — — — — 62869 18.0 — — /30 2500 — — — — 628432. 0.0 . — — 62870 12.0 — — Vl6 2000 62835 2. 5.01I62841 2. 10. 0 62 844 2. 10. 0 — — . 62871 1. 0.0 12. 0 5. 0 Vie 1200 628363.15.0 — 628454. 0.0 — — 628721. 0.0 15. 0 5. 0 Vl2 1200 628374. 5.0 — — 628464.10.0 — — ; 62 8731. 0.0 15. 0 5. 0 Vs 1850 62838 3. 10. 0 62 842 3.15.0628473.15.062858 4. 0.0 62874 1. 0.0 15. 0 5. 0 V, 2000 — — 628484. 5.062859 4. 10. 0 628751. 0.0 15. 0 5. 0 1350 — — — 62 849 6. 10. 0 62 860 7. 0. 0 62 876 1. 10. 0 — — I/I 2000 — — 628506.10.062861 7. 0.0628771.10.0 — — 1000 — — 628518. 0.062862 8. 0.0628781.10.0 — . — . v! 2000 — — — — 628527. 0.0628637. 0.0628792. 0.0 — — ;/3 700 — — — — 62 853 10. 0. 0 62 864 10. 0. 0 62 880 2. 0. 0 — — 2000 — — — 628548. 0.062865 8. . 0 0 62 881 2. 0.0 — — v! 1000 — — — — . 62855 10. 0. 0 62 866 10.0.0628822. 0.0 — — V, 500 — — — 162856 13.10.0 62 867 13.10.0 628832. 0.0 — — The prices include a normal cord or belt pulley. Motors quoted for on application for pressures other than 110 or 220 volts. Cl. 91, 2767, 75", 70'. 74 '. 89, 76 r. 993 Voltaic Electricity. Section 7: Induction Currents. No. 62884- 62884. 1:5. 51 972. 1 : 8. 62 888. 1 : 6. 62889. 1:7. 62.884. Direct Current Motor, series wound, on low base, Figure; output W'1 H. P., for 110 volt D. C., with switch, regulating resistance, tachometer and terminals .... 62.885. — i d e m, for 220 volts Direct Current 51,972. Direct Current Motor (shunt wound), Figure, rotary on base having vertical bearing; can also be used as Whirling Table; with cord pulley for driving Stirrers, electro- lytic stands, etc., and with attachment for inserting colour discs, etc; for 110 volts Direct Current. V8th H- P 51,973. - - i d e in, for 220 volts Direct Current For other kinds of current and other voltages — prices on application. 62.887. Sliding Resistance for regulating the speed of Nos. 51,972 and 51,973 62.888. Stepped Gearing for Laboratories, Figure 62.889. Direct Current Motor (shunt wound), F i g u re, with 4 -stepped cord pulley for ver- tical drive, and with gearing for horizontal drive, 110 volts, Vie"1 H. P., with regulating resistance and switch on one board 62.890. Electric Railway, Figure, with Track and special stand The motor can be removed from the chassis by loosening a few screws, and fixed on the stand. when it N used as a high-speed motor for rotating colour discs, etc. 62.891. Electric Railway, F i g u r e, with complete overhead system, on board, for working with 4 — 6 volts • 62.892. Model of a Controller as used on electric trains, with small motor (/tschr. f. d. phys. u. ehem. U. 17, 1904, p. 95) CI. 4670, 4687, 4955, 4196. £. 8. d. 8. 0. Oj 8. 10. 0 7. 0.0 7. r>. <> 1. 5.0 2. 0.0 6. 0.0 4. 16.0 3. 0.0 9. 10. 0 No. 62895. Electric Motors. Electric Power Transmission. 999 62890. 1:6. 62894. 2:3. 62891. 1:8. 62.893. Speed Counter with 2 spindles for working in both directions, Figure, counting from 0 — 5000, nickelled, with three different attachments for the spindles, in case . The first attachment is intended for centre-point shafts, the second for tapering shafts. The third attachment is used when neither centre-point nor taper is available or if the end of the shaft is not accessible. It is formed by a disc 24 mm diameter which is pressed on to the outer periphery of the shaft to be measured. 62.894. Hand Tachometer with spring axis for automatically setting the ranges, Figure, for 100 — 4000 revs., for dynamos and shafting, with attachment, in case, 60 mm scale diameter , .... The tachometer has three different ranges: 100 — 400, 300—1200, 1000 — 4000. In this new in- strument, provided with spring axis, the trouble of setting the range and transferring the cam to other axes is obviated. It is also impossible to damage the tachometer by over-running the pendulum shaft. 62,895. --idem, for 300 — 12 000 revs., with attachments, in case The ranges are: 300—1200, 900—3600, 3000—12000. t. 8. d. 0. 10. 0 5. 0.0 5. 0.0 Cl. 2781, 2795, 6501, 2792. 1000 Voltaic Electricity. Section 7: Induction Currents. No. 62 896- 62898. 1:4. 62 899. 1 : 4. Alternating and Three-phase Current. Universal Dynamos for generating Direct Current, Alternating and Three-phase Current: see £• «• pp. 992 and 994. 62,896. Alternating and Three-phase Current Machine after Weinhold, Figure (W. D. Fig. 578); can be used as a generator for single and three-phase current; as a Synchronous Motor or as an Asynchronous Motor (Induction Motor) for Alternating or Three-phase Current The Machine can easily be taken apart and a 4-pole rotor inserted for excitation with Direct Current (for using the machine as a generator or synchronous motor for mono-phase or three-phase current); or a short-circuited rotor can be inserted (for using the machine as an asynchronous motor for mono-phase or three-phase current). This Machine is excellently adapted for demonstrating the mode of action of the model machinas actually used in practice, as its construction is in accordance with that of such machines. Lantern Slides for explaining the connections and method of working of this small machine: gee No. 62,901. 62.897. Driving Device for hand drive, for above As a driving motor for above we can recommend No. 51,972 or 51,973, p. 998 (cf. the illustration). 62.898. Model of a Three-phase Motor, after Weinhold, Figure (W. D. Fig. 595) . . . This Model is used for studying the behaviour of a three-phase motor when various types of rotor are inserted. The model can be operated with machine No. 62,896 as used as a three-phase dynamo. Supplied with the model are a squirrel-cage rotor composed of laminated iron sheets and provided with copper bars; also a copperless rotor of sheet iron with paper layers between, and held together with four brass rivets; a solid wrought iron rotor and a hollow drum composed of sheet iron. 62.899. Reversing Switch for above, Figure (W. D. Fig. 599), to enable the model to be used also as a mono-phase motor 0. 16. 0 62.900. Polarisation Battery for starting or driving Motor No. 62,898 with mono-phase A. C. (W. D. p. 928) Cl. 4709, 5558, 55S7. No. 62 904. Alternating and Three-phase Current. 1001 62 902 C. 1:3. 62902D. 1:3. 62902E. 1:3. 62.901. Lantern Slides for Explaining the Connections and Mode o! Action of Generator No. 62,896, of A. C. Motor Model No. 62,898 and of the Demonstration Apparatus for rotary field experiments, No. 62,902 (W. D. Figs. 579—581, 583—587, 596 and 598). Each (a) Alternator (Fig. 579), (b) Magnetic Axis of the Alternator (Fig. 580), (c) Stator Winding of the Three-phase Machine I (Fig. 581), (d) Curve for Mono-phase A. C. (Fig. 583), (e) Curve for two-phase A. C. (Fig. 584), (f) Curve for three-phase Current (Fig. 585), (g) Star and Delta Connection (Fig. 586), (h) Stator Winding of three-phase machine II (Fig. 587), (i) Connections used as three-phase motor (Fig. 596), (k) Connections used as mono-phase motor (Fig. 598). 62.902. Demonstration Apparatus for Rotating Field Experiments (Battery A. C. Apparatus), after Weinhold, Figs. A— E (Ztschr. f. d. phys. u. chem. U. 6, p. 7; W. D. Fig. 582) The complete apparatus consists of: current distributing apparatus, Fig. A; Ferraris Double Coil Fig. B; Ferraris triple coil, Fig. C; 4-coil iron ring, Fig. D; 6-coil iron ring, Fig. E; magnetic needle and sheet-iron disc with agate cap; squirrel-cage rotor; glass disc with iron filings. The apparatus permits of carrying out the Alternating and Three-phase Current experiments in a convenient and practical manner. The following pertain to the apparatus: 1 — 2 Bunsen cells or an accumulator the current of which is transformed into Alternating or Three-phase Current by the distributing apparatus, Fig. A. This current flows through double or triple crossed different-coloured wire rings, Fig. B or C, in which a magnetic needle or an iron disc can be inserted. The bodies in- serted in the coils rotate under the influence of the rotating field. Instead of these iron rings an iron ring can be attached consisting of four or six coils and wound' with covered wires of different colour (Tesla Ring), Figs. D and E; with these it is possible to obtain synchronous rotation by inserting a magnetic needle or an iron disc; or asynchronous rotation may be produced by an iron ring wound with copper wire (short-circuited rotor). It is possible to show the migration of the lines of force of the field in a very pretty manner by means of a glass disc over which iron filings have been strewn. 62.903. - - idem, but with Weinhold Coils, for the Horizontal Projection Apparatus, instead of the crossed coils after Ferraris (W. D. Fig. 592) 62.904. Glow Wires for above (W. D. Fig. 591), consisting of three marble sockets, one with one wire, one with two wires in star connection, and one with three wires connected in delta, with protecting caps £. s. d. 0. 1.6 5. 10. 0 6. 0. 0 0. 15. 0 Cl. 2721, 2722, 2723, 2742, 2725. 1002 Voltaic Electricity. Section 7: Induction Currents. No. 62 905 — 62 905. 1 : 4. 62 908 A. 1:5. 62912. 1:5. 62 915. 1 : 10. 62,905. Model of a Three-phase Motor (Tesla Motor), for a pressure of approximately 2 volts, t. B. «i. Figure, with six groups of turns and short-circuited rotor. The winding is done in three colours and the connections are laid open, being connected in star and coloured. The apparatus is very comprehensive and suits No. 62,902 3. 0. 0 62.906. - - idem, for pressures of 6 — 12 volts, suitable for Dynamos No. 62,774 and 62,787/9 62.907. - - i d e m, for pressures of 20 — 40 volts, suitable for Dynamos Nos. 62,775/6 a, and suitable also for connecting to heavy current three-phase networks by the aid of Lamp Eesistance No. 61,504 „ 3. 0.0 3. 0.0 62,908. Model of a Two-phase A. C. Motor for a pressure of approx. 2 volts, same pattern ! as No. 62,905, with 4 coloured groups of turns, short-circuited rotor and coloured con- nections laid in the open, suiting No. 62,902 . 3. 0. 0 62.909. - - idem, for pressures of 6 — 12 volts, suiting Dynamos Nos. 62,774 and 62,787/9 62.910. - - idem, for pressures of 20 — 40 volts, suiting Dynamos Nos. 62,775/6 a, and also for connecting to heavy current two-phase networks by using Lamp Eesistance No. 61 ,.">(> I 62.911. Extra Price for Models Nos. 62,905 — 62,910 constructed as in Fig. 62,908 A . . . In this ronsti -iiciioii the motor can be canted over and the rotor easily removed. In addition to the short-circuited rotor are given in: 1 test magnetic needle in mount with handle; 1 iron cross: 1 iron disc divided into coloured plots: 1 glass disc and iron filings for demonstration the migration of the lines of force in the rotating field. With this apparatus it is possible to explain the three-phase or two-phase motors quite well. 3. 0.0 3. 0.0 1. 0.0 CI. 2726. 2727. 2728. 5572. X.i. 62 922. Models of Alternating and Three-phase Motors. 1003 62920. 1:5. 62916. 1 : 10. 62921. 1 : 6. 62922. 1 : 8. 62.912. Three-phase Motor and Two-phase Motor; both can be tilted over; on one board; £• s. d. Figure, with the same accessories as under No. 62,911, for approx. 2 volts, suiting No." 62,902 7. 10. 0 62.913. --idem, for pressures of 6 — 12 volts, suitable for Dynamos Nos. 62,774 and 62,787 to 62,789 7. 10. 0 62.914. - - idem, for pressures of 20 — 40 volts, suitable for Dynamos Nos. 62, 775/6 a and for connecting to heavy current networks by using No. 61,504 7. 10. 0 62.915. Alternator after Braun, Figure 6. 10. 0 62.916. Three-phase Motor after Braun, Figure, suitable for No. 62,915 (Ztschr. f. d. phys. u. chem. U. 5, p. 186) 7.10.0 Following are supplied as Accessories: magnetic needle rotating in fork; light iron cross on stand; sheet iron strip (with spring) on base; light iron piece with base; iron cross; iron ring and ring wound with copper wire as rotor; different coloured flexible leads. 62.917. Two-phase Alternator after Braun, construction as No. 62,915 6. 0. 0 62.918. Two-phase A. C. Motor after Braun, construction and accessories as No. 62,916 . 7. 0. 0 Apparatus Nos. 62,915 — 8 are very comprehensively built and permit of demonstrating in a very pretty manner the electrical transmission of power with polyphase A. C. Three-phase Current Model after Prof. Weiler (Ztschr. f. d. phys. u. chem. U. 5, p. 189; 6, p. 53), comprising: 62.920. Double Pachytrope after Weiler, Figure 2. 10. 0 62.921. Tesla Motor after Weiler, can be tilted back, Figure, with test magnetic needle, iron disc, iron cross for insertion, also glass plate for rendering the lines of force visible by means of the iron filings supplied 5. 0. 0 62.922. Crossed Coils after Ferraris, Figure 5. 0. 0 Cl. 5570, 2729. 6051, 4097. 1004 Voltaic Electricity. Section 7: Induction Currents. No. 62 923 - O-J-O 62 923. 1 : 6. 52 068. 1 : 6. 62 924. 1 : 5. 62926. 1:16. 62.923. Two-phase Alternator, Figure, with driving stand. The machine can be used instead of the double pachy trope for working Nos. 62,921 and 62,922 The machine can be employed for taking off both single-phase and two-phase alternating current. Two to three accumulators are used for exciting. Its mode of action is easily understandable as the coils are of different colours. 62.924. Commutator for Transforming Low Pressure D. C. into A. C., Figure, for the Whirling Table 52,068. Model for Demonstrating the Behaviour of a Short-circuited Rotor in the Rotary Magnetic Field, Figure, after Friedr. C. G. Miiller (M. T., Fig. 222), for placing on the Whirling Table; with a squirrelcage rotor which can be used both with and without an iron core 62,926. Apparatus for Demonstrating Synchronism and Asynchronism, Figure, after Gotze A cord rotates (1) the 4-pole periphery, representing the rotating field; and (2) the innermost disc provided with a thick point at the periphery (rotor as tunnel armature). The ring (stator) placed between these has black strips on the outer periphery (slots). The rotor disc can be rotated at the same speed or at a lower velocity by means of a stepped pulley, so that in the first place synchronism is present and in the other case asynchronism (slip)- 62,927. - - idem, smaller 62,928. Aluminium Egg after Thomson The hollow bipartite egg, which can be used either filled with iron filings or without these, rotates on its point in the rotating field. For making the experiment, use is made of one the Apparatus Nog. 62,905/14 in the tiltable pattern by placing the ring horizontally on a glass plate and inserting the egg in it. £. s. d. 8. 0. 0 0. 18. 0 2. 10. 0 10. 0. 0 7. 0.0 0. 6. 0 Cl. 6054, 4684, 2719, 4013. No. 62935. Alternating and Three-phase Current. 1005 62 933. 1 : 6. 62 930 B, 62931. 1 : 10 and 1 : 2. 62 932. 1 : 7. 62 934. 1 : 6. 62 935. 1 : 9. 62.930. Apparatus after Behrend for Demonstrating the Flow of Current in Three-phase Con- £• s. d. ductors, Figs. A and B (Ztschr. f. d. phys. u. chem. U. 5, p, 44) 0. 14. 0 62.931. -- idem, transparent, for the Projection Lantern, Figures 1.10.0 62.932. Apparatus after Moser, Figure, for showing the flow of current in three-phase leads By means of a gearing three glass tubes combined on a wood stand are rotated at the same speed. These glass tubes, representing sections of the three-phase leads traversed by the current, are provided with sheet iron strips. One side of all the latter is painted red and provided with an arrow, the others being blue and having arrows pointing in the opposite direction. Since these Iron strips are placed at angles of each 120° relative to each other, the apparatus gives, according to the different positions of the observer, a clear image of the momentary current-density (apparent width of metal strips) and of the current-direction (colour of the strip and direction of arrow) in the individual leads. 62.933. Model of a Star Connection, with three glow-lamps, on marble, Figure . . . . 62.934. Model of a Delta Connection, with three glow-lamps, on marble, Figure . . . 62.935. Board for Explaining the Star and Delta Methods of connecting in Three-phase Plants, after Gb'tze, Figure 2. 8.0 1. 10. 0 1. 10. 0 5. 10. 0 Cl. 2732, 407, 6059, 406, 2735, 6062, 3S89. 1003 Voltaic Electricity. Section 7: Induction Currents. No. 62936 — 62964. 1:4. 62966. 1 : 3. Electric Motors for Alternating and Three-phase Current, Figures: Type of Current System of Motor Approx. Effic. HP. Approx. r. p. m. For 110 Volts 50 periods For 220 Volts 50 periods Starting Resistance List No. £. s. d. List No. £. s. d List Xo. £. s. d. Mono- phase A. C. Commutator | j. Motor, /20 Speed variable || Yio 1700 1700 62936 62937 3. 10. 0 5. 0.0 62947 62948 4. 0.0 5. 10. 0 62956 62957 0. 15. 0 0. 15. 0 Motor with short-circuited Rotor; speed not variable VM »/• 0.175 0.35 0.7 1350 1400 1400 1400 1410 62938 62939 62940 62941 62942 3. 15. 0 4. 15. 0 6. 5.0 6. 15. 0 7. 10. 0 62949 62950 62951 62952 4. 0.0 5. 0.0 6. 15. 0 7. 10. 0 62960 62961 62962 1. 10. 0 1. 15. 0 1. 15. 0 Three- phase Current Motor with ; short-circuited Rotor; Speed not variable V,, '/• V« Vi 1320 1320 1400 1400 62 943 2. 15. 0 62 953 62944 3.15.0 62954 62945 6. 0.0 62946 6.15.0 62955 3. 0.0 4. 0.0 6. 15. 0 62963 2. 0.0 •:. .-. ,1. The prices are to be taken as including standard cord or belt pulley. Motors are quoted for on application for other voltages and periodicities. 62,964. Three-phase Motor, open type, Figure, for pressures of 6 — 12 volts, suitable for Machines Nos. 62,774 and 62,787—62,789 3. 4. 0 62,965. --idem, for 20—40 volts, suitable for machines Nos. 62,775— 62, 776a 3. 4. 0 Transformers. 62,966. Alternating Current Transformer, after Weinhold, can be taken to pieces; Figure; for use with open and closed magnet ic circuit (W. D. Fig. 590) 2. 4. 0 The transformer has three groups of windings — one group of 36 turns of thick wire, and two groups each of 1,000 turns thin wire. The transformer suits Machine No. 62896. The thin winding, however, can be connected for a short time to 100 — 120 volts when used with iron core. The following ratios can he produced 1:1; 1 : 28; 1 : :.:>. fl. 6053, 78"-. 2771, 375». No. 62972. Alternating and Three-phase Motors. Transformers. 1007 62 967 A. 1:5. 62 967 B. 1:5. 62 970. 1 : 6. 62 969 A. 1:5. 62 969 B. 1:5. 62,967. Alternating Current Transformer (Core Transformer), Figs. A and B, for demon- £• s. d. stration purposes; it can be taken entirely to pieces ............... I 3. 12. 0 The transformer has the following coils: (1) the inner one having 196 turns; (2) an outer one with 28 turns; (3) an outer one with 686 turns. The following ratios can thus be established: 1:7; 3.5 : 1; 1 : 24. The transformer is suitable for A. C. pressures from 24 to 44 volts when the inner coils is used as a primary coil, and the instrument therefore suits Machines Nos. 62,775/6 a. Suppose, for instance, that it is used with Machine No. 62,776; the following pressures can be obtained: 3"5 l 34 . — = 4.8 Volts; 34 . °"J = 119 Volts; 34 .= 1.4 Volts. 7 1 24 These pressures apply on no-load; they fall somewhat when load is applied. The thin wire ex- ternal coil can also be connected for a short time to 110 — 120 volts. 62,968. - - idem, for A. C. pressures from 7 — 14 volts, suiting Machines Nos. 62,774 and 62 787/9; Ratios: 1 : 7; 3.5 : 1; 1 : 24 62,969. Alternating Current Transformer, capacity up to 120 watts .... Figs. A and B, completely dismountable ; total The inner coil has 1000 turns; the five outer coils have 200 turns each and can be put in parallel and series with the copper pieces supplied. The ratios 1:5, 1 : 2.5, 1 : 1.67, 1 : 1.25, 1 : 1 can be established and it can be easily shown that the secondary pressure increases with the number of turns of secondary. When using the inner coil as a primary the transformer can be connected to pressures of 80 — 125 volts. 62.970. Alternating Current Transformer (Core Transformer), Figure; ratio 1 : 10, for primary pressures of 80 — 125 volts, secondary giving 8 — 12 volts; output about 100 watts On each core are wound a primary and a secondary coil over each other. 62.971. - - idem, for connecting to pressures of 24 — 44 volts, suiting Machines Nos. 62,775/6a 62.972. - - idem, for connecting to pressures of 4 — 14 volts; ratio 10 : 1, suiting Machines Xos. 62,774 and 62,787—62,789 3. 12. 0 6. 0.0 3. 12. 0 3.12.0 3.12.0 Cl. 2778, 2777, 6052, 5095, 5093. 1008 Voltaic Electricity. Section 7: Induction Currents. No. 62973 — 62 978 A, 62981. 1:7. 62.973. Three-phase Transformer (Core Transformer), Figure, with star connections; ratio 1 : 10; for primary pressure of 80 — -125 volts, secondary giving 8 — 12 volts; output about 150 watts 62.974. - - idem, for connecting to pressures of 20 — 40 volts, suiting Machines Nos. 62,775/6a 62.975. -- idem, for connecting to pressures of 6 — 12 volts, suiting Machines Nos. 62774 and 62,787/9 62.976. Alternating Current Transformer (Shell Type), Figure; ratio 5:1, for connecting to 24 — 44 volts primary pressure, for transforming the current of Machines Nos. 62, 775/6 a to five times the voltage 62.977. — idem, for pressures of 7 — 14 volts, suiting Machines Nos. 62,774, 62,787/9 . Inductive Repulsion. 62,978. Apparatus after Elihu Thomson, with complete Accessories, F i g s. A — H, for proving the repelling action of a Magnetic Field, generated by A. C.. on good conducting metal masses (Elektrotechn. Ztschr. 1890, pp. 387, 399 and 435) The following pertain to the complete apparatus and are supplied with it: 1 magnetizing Coil, renting on three pillars, with stage and apparatus holder, with sliding core formed of a bundle of thin iron wire; 1 Iron Membrane with tube (fastened to the apparatus itself in Fig. A) attached; 1 Balance with copper disc. Fig. B; 1 Grip with Fork for fixing one copper disc and one iron disc having copper rim, both painted with coloured sectors, Figs. C and D; 1 Iron Prism for tin- iron disc having copper rim, Fig. D; 1 Copper Hollow Sphere with wood ring and watch-glass as support, Fig. E; 1 Coil of coloured Aluminium Wire with cork and glow-lamp, also 1 Glass Vessel for carrying out I he experiment under water, Fig. F; 1 Copper, 1 Iron, and 1 Glass Disc; 1 Wood Frame with a copper ring suspended on fibres; Fig. G; 1 Copper Hollow Ring with attachment tube; 1 Copper Ring with pendulum suspension, Fig. H; 1 Wide Copper Ring; 1 Wide Aluminium Ring; 1 Mercury Gutter. For making the experiments with this apparatus an alternating current (110 — 120 volts) supplied direct from a power station, is suitable, of which 12 — 16 amperes are used for working the apparatus; when using D. C. this must be converted into a pulsating current by means of the \\elmelt Inter- rupter (No. 62,666, see below). Cl. 2780, 5379, 2820. £. s. d. 4. 10. 0 4. 10. 0 4. 10. 0 2. 10. 0 2. 10. 0 7. 10. 0 No. 62 978. Transformers. Inductive Repulsion. 1009 62978C. 1:5 62 978 F. 1:5. 629780. 1:5. 62 078 H. 1:5. The experiments which can be carried out with the above collection of apparatus are essentially the following: 1 . Singing Membrane, Fig. A. The iron core is slipped down to its lowest point in the coil and the iron membrane, with a space of approximately one millimetre, fastened above it. When the magnet is excited the membrane gives a tone corresponding with the frequency of the alternating current. 2. Balance with Copper Disc, Fig. B. The balance is inserted on the apparatus holder in such manner that the copper disc is 2 mm above this when the magnet is unexcited. When the current is closed the copper disc is then repelled. 3. Rotating Copper Disc, Fig. C. In the fork intended for the purpose is inserted the copper disc, fitted with coloured sectors and with axis; the disc is held horizontally above the magnet while the thick copper disc is inserted in such manner that one-half of the field is covered. 4. Rotating Iron Disc with Copper Rim, Fig. D. This is inserted in the fork in place of the previous disc; it is characterised by having two parts, a central iron part and an outer narrow copper margin. In this experiment it is best to raise the iron core somewhat so that it is projecting about 3 centimetres above the coil, and the iron prism is then set upon it. The fork is held in such wise that the disc is perpendicular; moreover, as in the preceding experiment, the field is partially covered by the stout copper disc. 5. Rotating Ball, Fig. E. If one-half of the electromagnet is covered with the thick copper disc and the wood ring, together with watch-glass and ball placed on the magnet, the ball is set rolling. This experiment works particularly well if instead of the wood ring and watch-glass the glass vessel is used and filled with enough water to allow the hollow ball to float. The rotation of the ball is then extremely rapid and takes place about a horizontal axis. 6. Spiral with Glow Lamp, Fig. F. Owing to the use of light material this device is so- constructed that it can only just sink under water. If the device, together with the water-vessel, is placed on the electromagnet and the latter excited, the lamp is rendered brightly incandescent. On the other hand a repulsion occurs; the spiral with the glow lamp is raised up in the water and the luminosity of the lamp appreciably decreases at the same time owing to the field becoming weaker. This is a very striking experiment. It is also possible to show with this arrangement the damping effect of different materials. If the copper plate is placed under the glass vessel the whole phenomenon almost disappears ; this is also the case to a lesser degree when the iron plate is used, while the glass plate is without influence. 7. Wood Frame with Ring, the latter suspended on fibres, Fig. G. The magnet core is lifted as far as possible out of the magnetizing coil, the frame and ring slipped over the same and the latter fastened to the carrier. Under the influence of the current the ring is raised up and is held sus- pended by the fibres. Owing to eddy currents in the ring this becomes considerably heated in a very short time; this heating also takes place to a corresponding extent in the other experiments. 8. Broad Aluminium and Copper Ring. The copper ring remains suspended approximately in the centre of the excited magnet core when placed above it, while the aluminium ring is entirely hurled away. 9. Ring with Pendulum Suspension. Fig. H. The apparatus is placed horizontally as shown in Figure and the core pushed into the coil somewhat so that the oscillating ring can swing out. The experiment is a variation of the preceding one. 10. Hollow Copper Ring with Attachment Tube. Some water is poured into the vessel and the small tube closed with a cork. The water, being heated by the eddy currents, evaporates; the cork is driven out with a pop and a jet of steam issues from the small tube. 1 1 . Mercury Trough. If this is filled with mercury and set upon the upright apparatus, the mercury is set into a wavy motion by inductive influence. Cl. 2821,2823, 2824, 2822, 2825. 2826, 2827. 64 1010 Voltaic Electricity. Section 7: Induction Currents. No. 62979 — 62 979. 1 : 7. 62 980. 1 : 5. 62,989. Apparatus after Elihu Thomson, same style as No. 62,978, but considerably larger 62.979. Apparatus after Elihu Thomson, smaller pattern than No. 62,978 and with simpler fittings, Figure The following are delivered with the apparatus as auxiliaries: 1 thick Copper Ring with 3 Cords, 1 Aluminium Ring, 1 Spiral with Glow Lamp, 1 large Copper Disc, 1 small Copper Disc with agate pivot, Stand and semi-circular Copper Disc, 1 Copper hollow Ring with annex tube, 1 Metal Cylinder. 62.980. Apparatus after Elihu Thomson, Figure, simple, with 4 rings, one each wide and narrow, of copper and aluminium This apparatus can be connected direct to a 110 — 120 volt lighting circuit, but a Resistance must be connected up between (e. g., No. 50,521, £ 2. 15. 0). 62,981. Magnetizing Ring after Elihu Thomson, No. 62,978 Figure, as addition to Apparatus This magnetizing ring, constructed of fine iron wire, slotted and wound, repels with a consi- derable amount of force a precious-metal coin, e. g., a half-crown or five-shilling piece, which is held in the narrow space between its poles, when the ring is excited by alternating current. With this apparatus also (which takes 5 — 7 amps.) use is made, as in the case of No. 62,980, of a series resistance (e. g., No. 50,521, £ 2.15.0) when the apparatus is used on 110 — 120 volt A. C. 62,666. Wehnelt Interrupter with 1 mm thick platinum pin, F i g. 62,666, p. 982, for con- necting apparatus Nos. 62,978 — 62,981 to 65 — 220 volt Direct Current 50,521. Series Resistance for above, 30 ohms, 5 — 25 amps. £ s. d. 12. 0. 0 4. 4.0 1. 8.0 1. 0. 0 3. 15. 0 2.15.0 Prof. E. Grimsel's Apparatus for the Experimental Introduction of Electromagnetic Units. The references refer to Vol. II, No. 2 of the Abhandlungen zur Didaktik und Phi- losophic der Naturwissenschaf ten : E. Grimsehl, Experimentelle Einfiihrung der Elektro- magnetischen Einheiten, published by Julius Springer, Berlin, 1907. £ s. d. 60,135. Magnetic Pole Balance after Grimsehl, Figure on p. 796 (also p. 3 of above work) 60,194. 2 Glass Rods with glass spheres in order to enable the pole balance to be used also 2.14. 0 0. 8.0 63,000. Apparatus for Demonstrating the Lines of Force Images of a linear Wire, also of a circular current similar to Berghoffs, cf. Fig. 62,370 L, N, O, p. 963 (Figs. 1, 2, 6, 7 1. 0.0 fiO.172. Font Terminal after Holtz. Figure on D. 799 . 0. 6.0 Cl. 3556, 2828. No. 63005. Induction Repulsion. Apparatus for the Electromagnetic Units. 1011 J 63 003. 1 : 6. 63 004. 1 : 4. 63 002. 1 : 8. 63 005, 60 135. 1 : 7. 63,001 . Brass Rod 50 cm long, with base and magnetic rod with suspension hook, Figure (see Figs. 3 and 4 of Grimsehl's work), without cell 63,002. Brass Disc with 3 Magnetic Needles for quantitative investigation of the magnetic field, Figure (loc. cit. Fig. 5) 63,003. Apparatus for Measurements of the Density of the Magnetic Field of Circular Currents, Figure (loc. eft. Fig. 8) £ s. d. 0. 7.0 0. 12. 0 1. 0.0 63.004. Device for showing the Dependence of the Density of the Magnetic Field on the Radius of the Current-carrying Ring, Figure (loc. cit. Fig. 9) [ 2. 8. 0 63.005. Complementary Parts to Pole Balance No. 60,135, in order to show with it the unit of electric current-density, Figure (loc. cit. Fig. 10) 0. 12. 0 Cl. 5921, 5922, 5919, 5917, 5920. 64 * 1012 Voltaic Electricity. Section 7: Induction Currents. ND. 1)3006 - 63 006 A. 1: 12. 63 006 C. 1: 12. 63006B. 1: 12. 63 006 D. 1 : 12 03.006. Coil for Generating a Homogeneous Magnetic Field, I) Quantitative Measurements on Electromagnetic Induction, Fig. D (loc. cit. Fig. 19); (c) Generation of Alternating Current, Fig. E (loc. cit. Fig. 23); (d) Calibration of a Ballistic Galvanometer (loc. cit. p. 35). 63.007. Electromagnet with 2 Foot Terminals, 1 Switch and Flexible, F i g u r e (loc. cit. Fig. 17; Griinsehl, Fig. 958), without cells 2. 5. 0 03,00*. Pole-determining Cell (loc. cit. p. 26) with double flexible soldered on 0. 3.0 ( 1. 5909, £913, 5911,5912. Xn. 63010. Apparatus for the Electromagnetic Units. 1013 63 006 E. 1: 12. 63 007. 63009. 1:5. 63 010 A. 63.009. Device for Generating a powerful Induction Current by moving a single conductor in a magnetic field, Figure (loc. cit. Fig. 18 ; cf . Grimsehl, Fig. 959), consisting of ring magnet, galvanoscope and a low resistance conductor 63.010. Device for Shunting small Potential-differences for Galvanometer Calibrations and the like, Figs. A and B (loc. cit. Figs. 20 and 21) 62,094. Paper Condenser, 2 mfds., for calibrating a ballistic galvanometer (Joe. cit. p. 36). 61.138. PohPs Mercury Switch for above , 61,302. Mirror Galvanometer after Weinhold, cf. Figure on p. 877 £ 8. d. 2. 16. 0 2. 5. 0 4. 10. 0 1. 4.0 7. 10. 0 Cl. 5910, 5918, 5910, 5915, 5914, 5923. 1014 Voltaic Electricity. Section 8: Electric Conduction in Gases. No. 63 020 — bed 63 020/24 a-e. 63028. 1 : 5. 63032. 1 : 6 Section 8: Electric Conduction in Gases. • ' ~ <" . r- ....... Geissler Tubes. Electric Eggs and Geissler Tubes evacuating automatically: see p. 830, items Nos. 60,577/8. , 6 Geissler Tubes of different shape and colour, in cardboard box. Figs. 63,020 to 63,024 a — e show a few of the shapes. List No. 63,020 63,021 63,022 63,023 63,024 Approx. length cm 12 16 20 25 30 £ 0.5.0 0.6.0 0.8.0 0.10.0 0.12.0 63.025. New Geissler Tubes consisting of five kinds of glass and lighting up in different colours (dark red, violet-purple, yellow, uranium green and neutral), about 20 cm long . . . 63.026. - - idem, approximately 30 cm long 63.027. - - idem, approximately 40 cm long £ 8. d. 0. 3. 0 0. 4. 0 o. :>. n 63.028. 6 Geissler Tubes of different shape and colour, Figure, each about 20 cm long, in small wood box with glass lid, with switch to permit of one tube after the other being lit up without having to change the leads 1. 12. o 63.029. - - idem, the tubes approx. 25 cm long .• • • 1. IS. o 63.030. - - idem, the tubes approx. 30 cm long 63.031. 4 Geissler Tubes approx. 20 cm long, in cardboard box, as follows: 1 tube with fluorescent liquid, 1 ditto with phosphorescent substance, 1 ditto with uranium glass beaker, 1 ditto with spirals 63.032. 6 Geissler Tubes, Figure, approx. 25 cm long, in cardboard box, as follows: 1 tube with fluorescent liquid, 1 ditto with phosphorescent substance, 1 ditto with 2 gases, 1 ditto with uranium and white glass, 1 ditto changing colour when heated, 1 ditto containing mercury which lights up when shaken 63.033. 7 Geissler Tubes approx. 35 cm long, in cardboard box, as follows: 1 tube with 2 fluorescent liquids, 1 ditto with 2 phosphorescent siilistiinco, 1 ditto with 2 Gases, 1 ditto with uranium and white glass, 1 ditto changing colour when heated, 1 ditto lighting up when shaken, 1 ditto with stratified light 63.034. Geissler Tube, with 1 fluorescent liquid, cylindrical, F i g 11 r e, approx. 25 cm long 63,035. -- idem, with 2 liquids, cylindrical, approx. 35 cm long 63.036. Geissler Tube, Figure, with four fluorescent liquids, with wood base, 30 cm high 63.037. -- idem, with 2 fluorescent liquids, on wood base, approx. 25 cm high . . . . 2. 0. 12. 0 0.16.0 1. 10. (> 0. 3. 0 0. 6. 0 0. 10. 0 0. 5.0 ( 'I. G.'.lfi, 6520, 6517, 6518, 6519, 2898, 2899. No. 63 051. Geissler Tubes. 1015 «feOP=^rr,. - ... .-...^csi>3 63039. 63 040. 1 : 4. 63042. 1 : 10. 63043. 1 : 5. 63046. 1:5. 63036. 1:4. 63048. 1:7. 63,038. Geissler Tube, large pattern, with 2 fluorescent liquids, approx. 50 cm high, Figure, on base Geissler Tubes, Figures, with pulverulent phosphorescent substances List No. 63,039 63,040 63,041 Number of Substances 124 Approx. Length cm 25 35 50 £ 0.3.0 0.5.0 0.12.0 63.042. Geissler Tube, Figure, with luminescent gas, bent simply, approx. 60 cm long 63.043. Geissler Tube, Figure, with stratified light, cylindrical, approx. 35 cm long . . 63.044. - - i d e m, 50 cm long 63.045. - - i d e m, 100 cm long 63.046. Geissler Tube with stratified light, Figure, with bulbs, approx. 50 cm long (cf. Gan.-Man. Fig. 678; Gan.-Kcin. Fig. 993) 63.047. - - idem, approx. 100 cm long 63.048. Geissler Tube, Figure, filled with three different gases, approx. 75 cm long . 63.049. - - idem, approx. 100 cm long 63 050. - - idem, approx. 150 cm long 63,051. - - idem, filled with 2 gases, approx. 35 cm long Spectrum Tubes: see p. 515 of this price list. : £ s. d. 1. 0. 0 0. 15. 0 0. 4.0 o. 6.;o 0. 10. 0 0.10.0 0. 18. 0 0. 15. 0 1. 0.0 1.10.0 0. 5.0 ci. 6585, 6522, 2904, 2905, 2901, 2906, 2900, 2907. 6521, 1016 Voltaic Electricity. Section 8: Electric Conduction in Gases. No. 63 052 — 63 052. 1 : 6. 63 055. 1 : 6. 63 057. 1 : 4. 63 058. 1 : 6. 63 060. 63 059. 1 : 5. 63 061. 1 : 9. 63 062. 63.052. Geissler Tube, Figure, with uranium glass bulbs outside and stratified light in £ s. d. the centre, 60 cm long 0. 9. 0 63.053. -- idem, 100 cm long 0.15.0 63.054. - - idem, 150 cm long 1. 5. 0 63.055. Geissler Tube lighting up by friction, Figure, 50 cm long 0. 8. 0 63.056. Geissler Tube, Figure, with mercury, lighting up by shaking, 35 cm long. . . 0. :.. u These tjibes are used in spiritualistic demonstrations for producing "spirit hands". 63.057. Geissler Tube, Figure, with mercury salts, the colour changing when heated, 35 cm long 0. 3. 0 63.058. Holtz's Tube, Figure, 40 cm long, double 0. 10. 0 The glow light passes in one direction only through the funicular apertures. The induction coil used must work without closing current. 63.059. Hittorff 's Tube, Figure, with base 0. 15. 0 The current takes the longer path through the spiral-shape bent tube, since the discharge at the points of the electrodes is prevented by the static electricity of the tube surrounding them. 63.060. Absolute Vacuum Tube, Figure 0. li'. n 63.061. Vacuum Scale after Cross, Figure, with stand and change-over switch, with tubes 50 cm long 2. 4. 0 The scale consists of six vacuum tubes evacuated to different degrees, viz., (1) luminous thu-ad (de la Rive's apparatus); (2) luminous band; (3) stratified formation; (4) Geissler vacuum; (5) Tesla vacuum; (6) Crookes's vacuum - - Rontgen vacuum. The change-over arrangement is double-pole thus obviating any illumination of the tubes which are not connected up. Vacuum Bulbs with different degree of vacuum and differently illuminating types of glass: 63.062. — with luminous strips, with base, Figure 0. 6. (I 63.063. — with luminous band, with base 0. 6. 0 63.064. — with Geissler light, with base (I. 6. 0 63.065. — with white stratified light (CO2), with base o. 7. 0 63.066. — with Tesla vacuum, with base. K i g u r e 0. 7. 0 63.067. - with Crookes vacuum and green phosphorescent glass, with base 0. 8. 0 f>X. 068. — with Crookes vacuum and bluish-white phosplmi ex-cut glass, with base 0. 8. 0 63,069. — with Crookes vacuum and red phosphorescent glass (didyminm-oerinm gloss), with base .... 0. 10. 0 63070. X-EayTube, for automatic evacution, with rubber tube attachemet, Figure . . 1. 0. For X-Ray Tubes for Practical Purposes: see p. 985. ( I. li'.IOS. 6524, 6523, 2911, 2910, 2913. 211 1^.29 14,6506. No. 63 580. Vacuum Tubes. 1017 63 066. 63 070. 1 : 6. 63 075. 1 : 10. 63071. 1:5. 63 076. 63077. 1:6. 63079. 1:5. Stands for clamping Geissler Tubes, F i g u r e, • for tubes to 30 cm length; prices without tubes : List No. 63,071 63,072 63,073 For 123 tubes £ 0.10.0 0.12.0 0.15.0 63.074. - - idem, for a Geissler tube to 60 cm length 63.075. Ozone Generating Tube after Siemens, Figure 63.076. -- idem, after G. Miiller, Figure : 63.077. Angle Mirror for Geissler Tubes, for manifolding the phenomenon, for tubes of 30 cm length, Figure 62,321. Electromagnetic Motor for rotating Geissler Tubes of length up to 20 cm, Figure on p. 958 52.057. Rotating Device for Geissler Tubes of 30 — 50 cm length, for the Whirling Table, Figure on p. 287 52.058. Poggendorff's Disc, for illuminating by Geissler Tube, Figure on p. 287, for shewing the intermittent course of the luminous flux (M. P. 9th Edn., Ill, Fig. 763), with a Geissler tube 63.078. Apparatus after De la Eive, for shewing the rotation of the electric luminous flux about an electromagnet, on stand, without commutator 63.079. - - i d e m, with commutator, Figure 63.080. - - idem, arranged so that it can be evacuated, with glass stopcock Cl. 6504, 5362, 5003, 3022, 3859, £ s. d. 0. 15. 0 0. 15. 0 0. 12. 0 1. 10.0 0. 16. 0 1.18.0 0. 15. 0 1. 2. 0 1. 8. 0 1. 10. 0 5538, 2916. 1018 Voltaic Electricity. Section 8: Electric Conduction in Gases. No. ii:u>8i — 63 087. 1 = 5. 63 088 a. 1 : 4. 63 088 b. 63089. 1:4. Cookes Apparatus for Experiments on Radiant Matter. The numbers of the tubes correspond to the figure-numbers of the work: 63.081. Radiant Matter, or the fourth Aggregate Condition, by William Crookes, German text by Dr. H. Gretschel, Leipsig, Quandt and Handel, 1879 The text beyond the bracket corresponds to the titles of the chapters. 63.082. No. 1. With l>;isc. Figure (M. I'. 9th Edn., Ill, Fig. 769), for demonstrating the dark space 0. 2.6 63.083. No. 2. Without stand, 3 tubes, Figure 63.084. --idem, 5 tubes, Figure 63,085. No. 4. With base, Figure (M. P. 9th Edn., Ill, Fig. 766) 63,086. No. 5. With stand, Figure (M. P. 9th Edn., Ill, Fig. 772) Kadiant Matter exerts a powerful phosphoro- genic action where it occurs. \l. 0. 8. It 0 0. 10. 0 1. 4. 0 0. 8. 0 0. 12. 0 Cl. 2921. 2918, 2917,2919, 2920, «099, 2923, 2924. No. 63 098. Crookes Tubes. 1019 63 093. 63.087. No. 6. With Stand, Figure 63.088. No. 7 a and b. With base, Figures 9th Edn., Ill, Fig. 770; Gan.-Eein. Fig. 994) 63.089. No. 8. With base, Figure (M. P., Eadiant Matter moves in straight lines. 63.090. No. 9. With base, Figure (M. P., 9th Edn., Ill, Fig. 771; Gan.-Man. Fig. 681; Gan.-Kein., Fig. 995) (radiant matter intercepted by a solid casts a shadow) .... 63,019. Cross-shadow Tube after Crookes-Fleming, Figure, for use with the magnet coil listed below 63.091. Tubular Magnet Coil for above, Figure If this magnet coil is slipped over the tube the crossed shadow is deflected to one side or the other according to the direction of the current in the winding. 63.092. No. 11. With stand, Figure (M. P., 9th Edn., Ill, Fig. 773; Gan.-Eein., Fig. 996) 63.093. No. 12. With base, Figure 63.094. No. 13. With base, Figure 63.095. No. 14. With Stand, but without magnet, Figure (M. P., 9th Edn., Ill, Fig. 780) 63.096. No. 15. With Stand, but without magnet, Figure 63.097. No. 16. With Stand, but without magnet, Figure 63.098. No. 17. With Stand, but without magnet, Figure] Eadiant Matter exerts a powerful mechanical action where occurring. Eadiant Matter is de- flected by a magnet. 0.11.0 0.11.0 0. 4.0 0. 16. 0 CM. 2925, 3563, 2928, 3564, 2930, ?928, 2931, 2927, 2929, 2932. £ 8. d. 1. 0. 0 0. 16. 0 0. 8.0 0. 12. 0 0. 15. 0 1. 0.0 0. 16. 0 0. 9.0 0. 9.0 1020 Voltaic Electricity. Section 8: Electric Conduction in Gases. No. 63099 - 63099. 1:3. 63105. 1:5. 63100. 1:6. 63 101. 1 : 4. 63 103. 1 : 5. 63 104. 1 : 6. 63.099. No. 18. With Stand, Figure 63.100. No. 19. With base, Figure j Eadiant Matter gene- • 63.101. No. 21. With base, Figure (M. P., 9lh Edn., Ill, j rates heat when im- Fig. 774; Gan.-Eein. Fig. 997) 63 106. l : 5. £ s. d. 0. 13. 0 I peded. 0. 8.0 0. 12. (I Puluj's Apparatus for Experiments on Radiant Electrode Matter. The numbers in brackets refer to the figure-numbers in the work: 63.102. Strahlende Elektroden-Materie, by Dr. J. Puluj, Vienna: Carl Gerolds Sohn . . . 63.103. (3) Apparatus for Demonstrating the Conduction of Heat in Mica and the phos- phorescence phenomenon connected therewith, Figure 03.104. (4) Apparatus for Phosphorescence in the Electric Shadow, Figure 63.105. (7) Tube with light and dark Cross, Figure 63.106. (38) Electric Radiometer, F i g u r e, with rotating mica cylinder . . 63.107. (40) - - with semi-cylindrical vanes 0. 2.6 0. 12. 0 0.32.0 0. 12. 0 1. 0.0 0. 9.0 63,108. (43) - - with phosphorescent vanes, Figure | 0. 15. 0 Cl. 2933, 2937, 2934, 2935, 2936, 0515, 2038. No. 63118. Puluj Tubes. 1021 63 113. 1 : 5. 63 108. 1 : 5. 63 111. 1:5. 63 112. 1 : 6. 63 114. 1 : 5. 63 115. 1 : 5. 63 116. 1 : 5. 63 117. 1 : 5. 63 118. 1 : 5. 63.109. (44) Electric Radiometer, with fixed vanes and rotating phosphorescent disc . 63.110. (45) - - with fixed vanes and 2 discs rotating in opposite, directions 63.111. (46) Phosphorescent Lamp, Figure <;:;.lli}. Puluj 's Lamp with 2 phosphorescent colours, Figure Under the action of cathode rays the two circular halves light up in the same colour but sub- sequently phosphoresce in different colours. 63.113. (50) Valve Tube, Figure When the vacuum is high the discharge can only pass in one direction through the tube, since this charge is influenced by the static charge of the glass walls. This tube is the original copy of the valve-tubes now used in X-ray practice for suppressing the light occurring on making. 63.114. (54) Zollner's Double Radiometer, Figure, with normal and abnormal rotation, with base 63,115. Vacuum Tube with phosphorescent mineral, Figure, with base 63,116. Vacuum Tube with three different phosphorescent minerals, constructed of phos- phorescent glass, Figure 63.117. Vacuum Bulb with butterfly, Figure, with base 63.118. Radiometer with bouquet, Figure, with base . . £ s. d. 0. 15. 0 1. 2.0 0. 14. 0 0. 18. 0 0. 8. 0 1. 0. 0 0. 13. 0 1. 4. 0 o.'ie. o 1. 10. 0- Cl. 2939, 2941, 3565, 2941 a, 2942, 2!i43, 2944, 2946, 2947. 1022 Voltaic Electricity. Section 8: Electric Conduction in Gases. .No. 63 119 — Tube with 5 Radiometer with Geissler Tube with phosphorescent Bouquet Tube Coral Minerals Tube with Tube with artif- Tube with Lava icial Ruby Double Spar Tube with Dolomite Tube with 2 Cape Dia- monds and 2 Ceylon Rubies and 1 Apatite. 63 124. 63 119. 1 : 8. 63,119. Collection of 8 Vacuum Tubes and 1 Geissler Tube, 55 cm high, with 2 fluorescent liquids, Figure The set comprises: 1 Tube with Coral (£ 0.12.6); 1 Tube with Dolomite (£ 0.12.6); 1 Tube with Double Spar (£ 0.12.6); 1 Tube with Lava (£ 0.12.6); 1 Tube with 5 different Phosphorescent Minerals (£ 0.16.0); 1 Tube with artificial Ruby (£ 1.2.0); 1 Tube with 2 Cape Diamonds, 2 Ceylon Rubies, and 1 Apatite (£ 2.10.0); 1 Radiometer with bouquet (£ 1.10.0) and 1 Geissler Tube with 2 fluorescent liquids (£ 1. 5. 0). 63.122. Vacuum Tube with 2 Cape Diamonds, 2 Ceylon Rubies, 1 Apatite (cf. Fig. 63,119) . 63.123. Vacuum Tube of Didymium-cerium Glass, phosphorescing red, with 7 ground glass stones, which when mixed with metallic oxides phosphoresce differently 63.124. Vacuum Double Bulb, after Winkelmann, Figure, for showing oscillatory dis- charges with spark-gap connected in parallel (Ztschr. f. d. phys. u. chem. U. 17, 1904, p. 37) Goldstein Tubes. 63.125. Deflection Tube, cathode consisting of 2 parallel aluminium wires, with base . . . 63.126. -- idem, cathode consisting o.f a star-shaped bent wire, Figure, with bu.sc. . 63.127. - - idem, cathode consisting of star-shaped cut-out concave mirror, F i g u r e, writh base 63,128. Vacuum Tube, with piece of gold or stamped aluminium sheet, with base, Figure 63,129. Canal Ray Tube, F i g u i «>, with base The cathode (a) consists of a grill-shaped aluminium sheet, while (b) is the anode. Violet rays are emitted from the canals formed by the grill. These rays are difficult to influence, and indeed this can only be done by powerful magnets, while the cathode rays which cause the phosphorescence of the glass and also the anode light-pencil in the lower tube can, as is well known, easily be deflected. £ s. d. 9. 10. 0 2. 10. 0 1. 7.0 1. 4.0 0.11. 0 0. 11. 0 0. 11.0 0.11.0 0. 17.0 Cl. 2948, 6509. NIL G3 135. Goldstein's Tubes. 1023 63 126. 1:5. 63 127. 1 : 5 63 128. 63 129. 63 132. 63 133. 63 134. 1131. 1:4. 63,130. Canal Ray Tube after Goldstein, new, simpler pattern; with polished wood base, Figure 63.131. -- idem, after Wien, with polished wood base, Figure This tube permits of showing the positive and negative charges of the cathode and canal rays. The perforated plate is earthed, the aluminium wire being the anode. If, then, the first electrode disc is connected with the negative terminal of a well-insulated induction coil, the cathode rays pass through the perforated plate, strike on the other disc and give a current of negative electricity if this latter disc is connected with a sensitive electrometer. If, now, the negative terminal of the induction coil is con- nected with the perforated plate (the earth connection remaining) instead of with the disc, a current of positive electricity is obtained from the cathode rays which are then emitted. 63.132. Goldstein Tube, Figure, filled with powdered sodium chloride, potassium chloride, potassium iodide, or potassium bromide. The substances mentioned change colour under the action of the cathode rays (Annalen der Physik und Chemie, Vol. 60, 1897, p. 491) The lead (a quite flexible stranded conductor) from a small induction coil (of not more than 3 cm spark-length) is slung fast to the platinum eyes. The thinner portion of the tube is clamped in a wood retort-holder or the like and while the current is passing through, the powder is approriately shaken up. In a few seconds this powder has assumed the characteristic colouring under the influence of the cathode rays, and this colour only disappears after a fairly considerable lapse of time. If only a large induction coil is available a 2 — 3 centimetre spark-gap must be put in parallel with the tube. 63.133. Goldstein Tube with powders phosphorescing in different colours; for tilting over, Figure Cathode Ray Tubes after Braun: see p. 899. 63.134. Vacuum Tube after Thomson, Figure, for studying the deflectivity of the cathode rays by static electricity and by magnets, with osmose regeneration to enable the vacuum to be maintained uniform 63,135. Wood Stand for above £ s. d. 0. 15. 0 1. 4. 0 0. 6.0 0. 12. 0 2. 5.0 0. 6.0 Cl. 2949, 2950, 6507, 6505, 3560, 6508, (5502,6503,3572. 1024 Voltaic Electricity. Section 8: Electric Conduction in Gases. No. 63 136 — 63136. 1:4. 63137. 1:4. 63138. 1:4. Wehnelt Valve Tubes. £ s. .I. 63.136. Small Valve Tube after Wehnelt, Figure (Drudes Ann. d. Phys. 1904, Vol. 14, p. 425; Ztschr. f. d. phys. u. chem. U. 18, 1905, p. 193) 1. 2. 0 This tube is used more particularly for converting weak currents of high frequency into pulsating direct current, and can be employed as a wave-detector (audion) for wireless telegraphy, as well as for demonstrating saturation -current phenomena. It has a cylindrical metal anode, and wire-shaped cathode coated with a metallic oxide. Metals coated with oxides behave very differently at high temperatures as regards the emission j of electrons. If a discharge tube having an incandescent electrode coated with an oxide and one or more metal electrodes is connected up to an A. C. circuit, the tube acts as a valve to the current, allowing the current to flow in one direction only. By utilising a number of tubes both phases of the A. C. can be used for conversion into pulsating D. C., or it is even possible to employ all phases of a triphase current. The oxide-coated metal electrode of the valve tube is heated by means of a small transformer or a few accumulators, a suitable regulating resistance being inserted until a yellow glow is attained (1300 to 1400° C.). 63.137. Large Valve Tube after Wehnelt, Figure, for transforming heavy currents, with base 1. 10. 0 This tube has a second anode contained in a cylindrical annex, by using which a magnificent stratified discharge is obtained. 63.138. Cathode Ray Tube (Valve Tube), Figure, with base 1.10.0 This is used for demonstrating the diffraction of the cathode rays into a circle in a homogeneous magnetic field (determining the ratio of charge to mass and velocity of the cathode ray particles) and , the practically parobolic curvature of the rays in the electrostatic field in this instance. The cathode has only a small oxide-spot from which a sharply defined cathode ray pencil issues when the current passes through. The experiments in which the tube has not to act as a valve are mosi conveniently carried out with a 110 — 120 volt D. C., in which case the incandescent oxide electrode serves as a cathode. 63.139. Liquid Resistance for putting in series with the Valve Tubes for preventing distur- bance at the electrodes The liquid used is water, which can be rendered slightly alkaline for reducing the resistance. 63.140. Vacuum Tube for Deflection Experiments after Braun-Wehnelt, with oxide cathode (Physikal. Ztschr. 6, p. 732), Figure, with small horse-shoe magnet and stand . 63.141. Vacuum Tube with Oxide Cathode and Phosphorescent Mineral, Figure, with base 63,144. Thomson's Luminous Sphere for demonstrating the luminous zones in vacuum bulbs inside a discharge circuit (Ztschr. f. d. phys. u. chem. U. 5, 1892, p. 207) 63,145. - - i d c m, larger, specially adapted for the experiment for demonstrating the elec- tmdcless circular current in gases o. i.o 2. 0. l> 1. 10. It 0. 3. 0 o. 14. o; rl. 5402. 3588, 3509. No. 63 156. Wehnelt Valve Tubes. Vacuum Tube Illumination. Theory oJ Electrons. 1025 63 141. 1 : 4. 63 148. 1 : 5. Vacuum Tube Illumination after Mac Farlane Moore. 63.146. Vacuum Vibrator, Figure, with holder, magnet coil, and connecting terminals (Elektrotechn. Ztschr. 1896, p. 637) 2. 14. 0 A Wagner hammer interrupter vibrating in an evacuated glass tube produces such clear inter- ruptions that the self-induction currents induced in the magnet coil are sufficient to excite vacuum tubes. 63.147. Vacuum Vibrator alone 1.2.0 63.148. Electrodeless Tube, Figure, 0.5 m long 0. 6. 0 Section 9: Electron Theory and Radioactivity. Apparatusfor School Experiments on theTheory of Electrons, after Prof. G. Mahler. (cf. Ztschr. f. d. phys. u. chem. U., 22, 1909, p. 98.) 63,149. Elder Pith Ball on 3 m long silk fibre 63.150. Hollow Polished Metal Sphere, 100 mm diameter, on insulating stand 60,176. 2 Leaf Electroscopes Each £ 0. 10. 0 63.151. Small Wood Board with 2 terminals for stretching glow wires Glass Rods, Ebonite Rods, see p. 797; Influence Machines, p. 819; Electric Needles, p. 798 of this price list. 63.152. Leyden Jar, 16 cm high, with hollow ball 100 mm diameter 63.153. Ebonite Disc 200 mm diameter, coated one side with tinfoil 63.154. Cardboard Disc with hole 6 mm diameter 63.155. - - idem, with a number of concentric holes 63.156. Electroscopic Powder with pulverising apparatus 62,731. Apparatus for showing that the Air is Ionised by Rontgen Rays, cf. p. 986 . . . 63,046. Vacuum Tube with stratified light 60,012. 2 Bar Magnets for above Each £ 0. 2. 6 Tubes for Deflecting Cathode Rays: see p. 1019. £ s. d. Cl. 3570, 2958, 3571,2959. 0. 0.6 0.18.0 1. 0.0 0. 4.0 0.14.0 0. 3.0 0. 0.3 0. 0.4 0.10.0 2. 0.0 0.10.0 0. 5.0 65 1026 Voltaic Electricity. Section 9: Electron Theory and Radioactivity. No. 63 159 — 63 159. 63163. 63 163. 63168. 1 : 1. 63.159. Vacuum Tube after Perrin, for demonstrating the negative charge produced by cathode rays, Figure, on base 63.160. Glow Lamp for the Edison Effect, Figure The electrons issuing from the incandescent carbon loop give a negative charge to an insulated aluminium sheet contained in the same. A sensitive galvanoscope between aluminium sheet and posi- tive pole of the lamp, gives a deflection, while showing no current between aluminium sheet and negative lead of lamp. 63.161. Glass Plate with covering, for the Hall Effect Apparate for Opto-electrical Experiments. 63.162. Zinc Disc, amalgamated, with insulating holder, with terminal The zinc disc is connected with a sensitive electrometer by a thin wire. If the electrometer be negatively charged, a quick discharge occurs when the zinc disc is brilliantly lighted by an elec- tric arc lamp, or, better still, by a mercury vapour lamp made of glass permeable to ultra-violet rays (Uviol Lamp No. 63,198). When the electrometer is positively charged no discharge occurs on illumination. The uncharged electrometer becomes positively charged when the illumination is applied. The first two experiments can be carried out with a sensitive leaf electroscope (e. g., 60,176, 60,186, 60,196, 60,202); a sensitive electrometer (e. g., quadrant electrometer No. 60,720) is necessary for the third experiment. The zinc disc must be freshly amalgamated before use. When ultra-violet light is allowed to fall upon a spark gap connected up to an induction coil it is bridged over at a considerable distance, as without the action of light (cf. Gratz, Die Elektrizi- tat, 15th Edn., p. 348). A transparent gypsum slab does not effect the discharge much, while a glass plate annuls it, since the action chiefly depends on the ultra-violet light. 63.198. Uviol Mercury Vapour Lamp with Stand, for connecting to 65 — 220 volts D. C. . 63.163. Potassium Cell after Elster & Geitel, Figure (Wied. Ann. d. Phys., 1894, Vol. 52, p. 433) The cell also acts with white light and gives an opto -electrical current. It is placed in a dar- kened box and put in series with a very sensitive mirror galvanometer of high resistance and with a 100 — 200 volt battery, the tension being regulated in such manner that no current overflows at the cell. The surface of the potassium metal is connected to the negative pole and a wire-shaped aluminium electrode with a positive pole. If the surface of the potassium is lighted by sunlight or a sufficiently strong source of light, a passage of the current takes place in the cell, the intensity of which is proportional to the strength of the light. 63.164. Sodium Cell for the same experiment 63.165. Potassium-Sodium Amalgamating Cell 63.166. Sodium Cell with Quartz Window 63.199. Sodium-Amalgam Cell for opto-electrical discharge by daylight (cf. Gratz, Die Elek- trizitat, 15"' Edn., Fig. 337) Radioactivity. 63,167. Radium Cell, F i g u r e, without charge The radium cell consists of an ebonite chamber containing on one side a small flat cavity fur the radium bromide charge. A mica plate secured by a metal cover having a hole in the middle, closes the cell off on this side. The active rays of the radium bromide can issue at this open side of the cell through the mica plate, the back of the cell acting as a screen. Radium Bromide for above quoted for on application. For tilling the cell ."> to In milligramme radium bromide are employed. £ s. d. 1.10.0 1.14.0 0. 4.0 0. 5.0 5.10.0 2. 0.0 1. 15.0 3. 0.0 3. 0.0 1. 2. 0 0. 3.0 Cl. 1965, 6510,5277,3821.1966 No. 63 180. Opto-electricity. Radioactivity. 1027 63 170. 1 : 3. 63 180. 1 : 2. 63.168. Spinthariscope, Figure The apparatus consists of a small brass tube on the back end of which is a small light screen of zinc sulphide. In front of this screen a metal pointer is fitted which can be moved up and down over the screen externally by the finger. At the lower side (i. e., the side opposite the luminous screen) the indicator contains a little radium bromide. The radium-bromide permanently radiates and the rays encounter the zinc sulphide screen, which lights up like a billowy, sparkling sea of light when the screen is looked at through the magnifier placed on the front of the apparatus. The observation must be made in a perfectly dark room and the eye must rest for some time (5 to 10 minutes) so as to become rid of other impressions and thus observe the phenomenon tho- roughly well. 63.169. Spinthariscope without Magnifier, for use under the microscope 63.170. Case containing Collection of Radioactive Preparations, Figure The case contains: 1 spinthariscope (No. 1); 1 piece uranium pitch blende (No. 2); 1 piece wille- mite (No. 3); 1 piece Kunzite (No. 4); 1 piece calc-spar (No. 5); 1 radium cell (No. 6); 1 cube fluorspar, 13 mm side (No. 7); 1 barium platino-cyanide screen (No. 8) and one zinc-sulphide screen (No. 9). The various apparatus and preparations contained in the collection are also sold singly at the prices named below. The radium cell included in the collection is unfilled. If it is desired that it should be supplied filled with radium-bromide the quantity and quality of the material desired should be specially in- dicated. Prices quoted on application. 63.171. Uranium Pitchblende for comparative experiments on radium, in pieces of 50 — 300 grammes. Per 100 g 63,17'2. Uranium metal, quite pure, for use as unit of radiation Per gramme 03,17.'!. Willemite, phosphorescent, in pieces of approx 30 g 63.174. Kunzite, fluorescent, in pieces of 6 — 8 grammes 63.175. Calc-spar, approx. 40x15x6 mm 63.176. Fluorspar Cube, approx. 13 mm side 63.177. Barium platinocyanide Screen, 65 x45 mm 63.178. Zinc-sulphide Screen, 65x45 mm 63.179. Mixture of Radium and Zinc-sulphide, in small sealed glass tube, phosphorescing in the dark . . . 63.180. Apparatus for Studying Induced Radioactivity, Figure (cf. Besson, Le radium et la radioactivite, Paris, 1904, Fig. 21) The apparatus consists of a small cylinder and a glass flask connected by a double-bent tube; the tube is provided with a stopcock. The cylinder receives the concentrated solution of a radium salt and the glass flask the material which it is desired to render active, or the preparation which it is desired to render phosphorescent. The communication is effected by opening the stopcock and interrupted again by closing it. Both the cylinder and the glass flask are provided with tube and stopper in order that the materials can be changed. i s. d. 1. 8.0 0.12.0 5. 0.0 0. 6. 0 0. 3. 0 0. 8. 0 0. 10. 0 0. 6. 0 0. 12. 0 0. 8. 0 0. 6. 0 1. 0. 0 0. 8.0 Cl. 1967, 3126. 65* 1028 Voltaic Electricity. Section 9: Electron Theory and Radioactivity. No. 63 181 — 63 181. 1 : 4. 63 184. 1 : 4. 63 182. 1 : 6. 63.181. Electrometer, Figure, specially arranged for investigating radioactive substances. The apparatus corresponds to a Kolbe No. 61,096 Aluminium Leaf Electrometer, p. 802, and has a projection-calibration scale and amber tube in ebonite plug, one extra ebonite plug with amber tube, conductor rod and paper leaves. The instrument has a small stage at the side on which are placed the substances to be investigated. The electrometer is charged by influence by allowing an ebonite rod, electrified by friction, to act on the upper plate. The aluminium leaf is deflected from its perpendicular position and conserves this deflection for a very long period, provided no radioactive substances are allowed to act on it. If, however, radioactive substances in the form of fine powder are placed in a thin layer in a special sheet iron plate, and put on the lower slab, the rays emitted render the air between the two plates conduc- tive, thus discharging the electrometer. The velocity with the which the aluminium leaf moves during the discharge gives a measure for the intensity of the radiation of radioactive substances. 63.182. Electrometer after Curie, Figure, on wood stand, with reading microscope . . The Electrometer is built into a metal housing covered by two glass plates. The two horizon- tal metal plates are covered by a cap, this being removed when introducing the substances and replaced for carrying out the 'measurement. This part of the apparatus can be easily cleaned and any trace of dust of radioactive substances should be avoided. The electrometer proper is well closed, since the necessary cleaning would be attended with difficulties. The electrometer is charged at the upper knob, protected by a special cap. For taking the substances to be introduced special small plates are supplied with the apparatus. In order to estimate the velocity of the leaf the lower and of the same should be observed by means of the fixed microscope having micrometer ocular. With the aid of a seconds clock the linn- is noted which is necessary for the image of the front edge of the leaf in the micrometer to move over a definite number of divisions. 63,183. — idem, without reading microscope 6. 0. 0 £ s. d. 4. 0.0 7. 10. 0 63,184. Simple Portable Electroscope for investigating weakly radioactive substances, Figure 2. 0. 0 Cl. 2078, 6114,3699. No. 63 204. Radioactivity. 1029 63 200. 1 : 8. 63 204. 1 : 10. Accessories : 63,185. Reading Telescope with micrometer ocular for same (for accurate measurements) £ s. d. 2. 16. 0 63,186. Ebonite Rod with Rubber '. I 0. 3. 0 63.187. 6 Closing Discs 63.188. Disc with Uranium Oxide a* radioactivity standard 63.189. Carrying Case for the Electroscope with accessories 63.200. Fontactoscope after Engler and Sieveking, Figure, for determining the radioac- tivity of waters (Schiffner, Eadioaktive Wasser in Sachsen), with accessories .... The foregoing price includes: (a) 1 Electroscope after Elster & Geitel, modified by Engler & Sieveking, with amber insulation (£ 3.5.0); (b) 1 Arrangement Jor Parallax-free Reading of the Deflection of the Leaves, consisting of a scale with mirror and sliding magnifier (£ 1.13.0); (c) 1 Dissipation Cylinder for suspending (£ 0.10.0); (d) 1 Can of nickelled brass sheet, 10 litres content, for spring water testing (£ 1.0.0); (e) 1 Can with plate, of nickelled sheet brass, for investigating solids (£ 1.3.0); (f) 1 Rubber Stopper with glass stopcock, for closing the aperture at the bottom of the can (£ 0. 7. 0); (g) 1 Rubber Stopper for closing this aperture during transit (£ 0.1.0); (h) 1 Large Rubber Stopper for closing the neck of .the can (£ 0.4.0); ( i) 1 Melta Lid for the neck of the can, arranged for setting up the electroscope (£ 0.15.0); (k) 1 Zamboni ,Drv Pile, 300 — 350 volt pole-tension, for charging the electroscope; as desired, with a stand for suspending the pile, or with a metal sheath, in which both poles are insulated, so that the pile keeps well (£ 1.13.0); (1) 1 Transit Cass with leather carrier (£ 2.2.0). Instead of the dry pile listed under No. 63,200k we supply, if desired: 63.201. Zamboni Pile with protecting neck. The poles of the pile are laid in ebonite plates having artificially enlarged surfaces. A special needle permits of utilising also 0. 8. 0 1. 0. 0 0. 18. 0 12.10.0 sub-divisions of the pile (alone £ 2. 18. 0) Extra price 63.202. Case for Electrometers Xos. 63,200 a and 63,200 b, for use where a carrying case is not desired. Decrease in price for this Case instead of Transit Case 63.203. Case, for Electrometer No. 63,200 a and b alone 63,204. Electrometer Jor Radioactive Measurements, especially on waters, after H. W. Schmidt, Figure, Travelling Apparatus with reading microscope, dissipation vessel with level, stand, agitating flask, rubber bellows, rubber tubing, stop-watch, thermo- meter and charging rod (Physikal. Ztschr. Vol. 6, 1905, p. 561) |14. 0. 0 1. 5.0 1.10.0 0. 8.0 A complete special list concerning apparatus 63,200 — 63,204 sent on application. Exact directions for use are appended to each apparatus. Cl. 5388, 5265. 1030 Voltaic Electricity. Section 10: Electrical Oscillations. No. 63206 — Section 10: Electrical Oscillations. Wireless Telegraphy. 63 206. 1 : 8. Apparatus for Tesla's Experiments with Currents of High Frequency and Tension. (cL in this respect Ztschr. f. d. phys. u. chem. U. 9, 1896, p. 139.) (a) For small-scale Experiments with an induction coil of 60-150 mm spark-length. 63,206. Complete Apparatus for the Experiments with Currents of High Frequency and Ten- sion, after Tesla, with Elster & Geitel High Tension Transformer, Figure. . . . , 9. 10. 0 The apparatus consists of: 1 Leyden jar 40 cm high and 1 spark micrometer with zinc points, all mounted on polished oak board; 1 Elster & Geitel high tension transformer, of. Fig. 63,210, and 1 sparking pillar, cf. Fig. 63,216; 2 induction spirals insulated from each other by a glass cylinder, the secondary spiral carrying a glow lamp, cf. Fig. 63,213; 1 copper stirrup with 1 gl&w lamp for the impedance phenomenon, cf. Fig. 63,219; 2 brass plates as conductors, cf. Fig. <>.'?. 222; 2 circular thick copper wires for concentrating the brush discharges, cf. Fig. 63,225; 2 parallel wires for the same experiment, cf. Fig. 63,226; 1 Tesla lamp with a fine, long filament and an external electrode and with fittings, cf. Fig. 63,227; and 1 electrodeless Tesla tube 50 cm long, cf. Fig. 63,228. In addition it is advisable to provide a few of the Tesla Tubes listed under Nos. 63,232 — 63,240. (b) For Large-scale Experiments with an Induction Coil of 200—600 mm spark-length. The most important apparatus and those suitable for forming a collection of in- struments on the subject are marked f. t 63,207. Leyden Jar Battery, Figure, with 2 jars 40 cm high, for connecting in sc- ries, on polished wood board j 2. 6. 0 CI. 6118. No. 63211. Tesla Experiments. 1031 63 207. 1 : 6. 63 208. 1 : 5. 63 210. 1 : 6. 63 211. 1 : 9. t 63,208. Spark Micrometer, Figure, in black glass box, on serpentine stone base 63,209. - - idem, with silencing box of wood t 63,210. High Tension Transformer, Figure, without oil insulation, after Elster & Geitel, with two differently wound secondary coils, 425 mm high, for induction coils to 250 mm spark-length t 63,211. -- idem, considerably larger, Figure, 640 mm high, for induction coils of 250 — 600 mm spark-length £ s. d. 1. 6.0 1.16.0 3.10.0 5. 0.0 Cl. 3039, 2981, 2970, 2984. 1032 Voltaic Electricity. Section 10: Electrical Oscillations. No. 63212 — 63215. 1:17. 63,212. High Tension Transformer with Oil Insulation, after Klstcr ^ C.eitel, Figure, with a secondary coil, 700 mm high, for induction coils of 300 — 600 inin spark- length ....'. f 63.21:5. 2 Induction Spirals separated by a glass cylinder, with glow lamp. Figure (i.i.-'ll. Apparatus after d'Arsonval, Figure, comprising a 1.7 m hijrli s]>iral for con- taining a man, with a spiral having glow lamp fixed on a belt 63,215. -- idem, of. Fig. 63,215, 1.75 m high and 0.75 m diameter, provided with a door for convenience ol entry. Price without accessories illustrated . . ; A complete description and din-rtiops for u 6132. No. 63 224. Tesla Experiments. 1033 63 216. 1 : 5. 63217. 1:7. 63 219. 1: 17. 63216, 63221. I : 6. 63222. 1:12. t 63,216. Discharger, Figure, with ebonite pillars on polished wood board 63.217. -- idem, larger, on iron feet, Figure .. 63.218. Whirl, Figure, for fitting on the high tension transformer 63 224. 1 : 30. £ s. d. 1. 0.0 t 63,219. Copper Stirrup, Figure, with 1 glow lamp, for the phenomenon of impedance t 63,220. --id e m, with 4 glow of 35, 20, 10 and 5 volts pressure 63,221. - - idem, after Kann, Figure, with 1 glow lamp and with folding stirrup, for showing that self-induction is the cause of the phenomenon (Ztschr. f. d. phys. u. chem. U., 20, 1907, p. 247). Without the dischargers No. 63,216 illustrated .... f 63,222. 2 Brass Plates, Figure, as conductors for producing a high frequency field 63,223. Leyden Jar, 16 cm high, with detachable point, for proving the positive flow in the neighbourhood of the transformer pole 63,224. Large Brass Conductor, Figure, for experiments on distance effect, 90 cm long, 26 cm diameter, nickclled, on 1.5 m high glass pillar, with large iron tripod . 1.16.0 0. 4.0 0.12.0 1. 8.0 0.16.0 0.18.0 0. 5.0 5. 0.0 CI. 2971, 2988, 2973,6116,2974,2990. 1034 Voltaic Electricity. Section 10: Electrical Oscillations. No. 0322.-) — 63228 — 63231. 63225. 1:18. 63235. 1:9. 63 227. 1 : 7. 63226. 1:11. 63 233. 1 : 5. 63 236. 1 : 6. 63 237. 1 : 6. t 63,225. 2 Circular Stout Copper Wires, Figure, for concentrating the brush dis- charges 0. 8. 0 t 63,226. 2 Parallel Copper Wires, Figure, for producing a luminous band 0. 6. 0 t 63,227. Tesla Lamp with a fine long Filament and an external Electrode, Figure, with fitting for fixing to high tension transformer 0. 8. 0 63.228. Electrodeless Tube, jagged shape, 0.5 m long, Figure 0. 4. o 63.229. - - idem, 1 m long 0. 6.0 t 63,230. -- idem, 1.5 m long 0. 8. o 63,231. -- i d e m, 2 m long 0. 10. (I t 63,232. Electrodeless Tube, straight pattern, 0.4 m long 0. !.<> 63,233. -- idem, with two external electrodes, Figure 0. 5. 0 t 63,234. Evacuated Bulb without electrodes, Figure 0. 5. o 63,235. Rectangle of Tubes without electrodes, Figure 0. (i. o t 63,236. Evacuated Bulb with one electrode, Figure 0. (i. o 63,237. Bulb with an Electrode and phosphorescent cross, Figure 0. 12. 0 t 63,238. Bulb with an Electrode and phosphorescent mineral, Figure 0.15.0 t 63,239. Ebert's Phosphorescent Lamp with 13 electrodes, Figure (Wied. Annalen, Vol. 53, 1894, p. 159) 0.16.0 63.240. Vacuum Tube after Elster & Geitel, for deflection experiments, Figure ... 0.12.0 For further details as to the tubes, kindly refer to directions for use which will be sent on application. 63.241. Complete Set of Tesla Apparatus after Weinhold, for induction coils of 60 — 150 mm spark-length (W. TL, pp. 939—944 [832—837], Figs. 605—607 [550—552]) 6. 10. 0 The following are fitted on a wood board: 1 large Leyden Jar. I spark micrometer, 1 oil-insu- lated transformer (Pig. 63,242). In addition the following are supplied: 1 copper wire ring for the impedance experiment (Pig. 63, 241 A). 1 impedance stirrup, 2 wire spirals, one with glow lamp for Cl 2975,2978, 6113,2976,2994,2995, 2983,2996,2997. No. 63 250. Tesla Experiments. 1035 /I 63 238. 1 : 6. 63 239. 1 : 6. 63 241 A. 1:4. 63240. 1 63242. 1:4. 63 249. 1 : 8. 63250. 1:8. transformation; 2 insulating stands, 2 copper rings and 2 copper wires for producing a luminous wall, 2 wire nets for generating a high frequency field, 1 electrodeless tube, 1 glow lamp with one elec- trode, 1 wood piece with two terminals. 63.242. Oil-insulated High Tension Transformer after Weinhold, separately, Figure (W. D., Pig. 607 [552]), for induction coils of 60—150 mm spark-length 63.243. - - idem, larger, for larger spark coils Leyden Jars after Lodge, for demonstrating Electric Resonance: see p. 838, Nos. 60,646 — 30,648. 63.249. Leyden Jars for Lodge's Resonance Experiment, after Weinhold, Figure (W. D., Fig. 608 [553]) 63.250. Apparatus for Generating Currents of High Frequency and Voltage by Resonance, after Oudin, Figure, consisting of 1 spark micrometer with zinc bulbs and protec- ting case, with ebonite grip; 2 Leyden jars each 160 mm high and 1 Oudin Eesonator, mounted on one polished base together with all necessary connections £ s. d. 2. 10. 0 3.12.0 1. 10. 0 7. 10. 0 Cl. 2998, 2999, 3000, 6528, 6527,6531,3003. 1036 Voltaic Electricity. Section 10: Electrical Oscillations. Xo. 63251 — 63 252, 63 210, 63 259, 63 209, 62 513. 1 : 12. Apparatus after Seibt for demonstrating stationary electric waves. 63,2'ti. Vacuum Tube for demonstrating the oscillatory character of Leyden Jar Discharges, £ 8- d- after Paalzow (M. P. !»"' K.ln. III., p. 892) 0. 3. 0 Tlic nine, fed from an induction coil, gives a luminous band which is deflected to cither side of the tulic. according to the direction of the current in the tube, when a strong magnet is Id-ought near it. If a small I.eyden jar is inserted in the circuit of the induction coil the band is always de- flected in both directions. Cl. 5126. No. 63256. Resonance of Electric Waves. 1037 63 256, 63 254, 63 259, 63 209, 62 513. 1:10. Set for demonstrating the resonance of electric waves by Seibt's Method. 63 255. 1 : 5. £ s. d. Seibt's Apparatus for demonstrating the Resonance of Electric Waves. (E. T. Z., 1902, pp. 315 et seq; Phys. Ztschr., 4, 1902, p. 99.) 63.252. Large Resonance Coil after Seibt, Figure, 2 m long, on base, with two lateral wires 2. 5. 0 63.253. - - idem, with evacuated glass tube on one side and wire on the other, 1 m long 3. 0. 0 63.254. Resonator after Oudin, with 2 terminals, with ebonite grip for tuning accurately, Figure 2.8.0 63.255. Variable Self-induction (Exciter Solenoid), Figure 3.6.0 63.256. 2 Small Resonance Coils with ebonite pillars on serpentine stone bases, of different winding and colour, Figure Each £ 1. 2. 0 2. 4. 0 Cl. 5136, 3002. 1038 Voltaic Electricity. Section 10: Electrical Oscillations. No. 63 257 — 63 267 A. 63 262. 1 : 8. 53 508. 1 : 6. 63 267 B. 63 267 C. 63.257. Extra Resonance Coil on base, with Geissler Tube, for showing the tuning of a receiving station for wireless telegraphy 63.258. Extra Resonance Coil on base, for showing the screening effect For this experiment Coil No. 63,257 must be available in addition to the above. 63.259. 2 Leyden Jars with metal fittings, 26 cm high, medium capacity, cf. Fig. 63,207 . 63.260. 2 Extra Jars of higher capacity Each £ 0. 6. 0 63.261. 2 Extra Jars of lower capacity Each £ 0. 6. 0 63.262. Oil Condenser with variable capacity, Figure, for use instead of the Leyden Jars 63,210. High Tension Transformer after Elster & Geitel, with two secondary coils of different winding, Fig. 63,210, p. 1031 or : 63,211. -- idem, larger. Fig. 63,211, p. 1031 63.208. Spark Micrometer with flat thread, high pitch regulating screw on long ebonite handle, in glass box, on serpentine si one base. Fig. H3,208, p. 1031 63.209. — idem, with protecting silencer box A complete special list, with description, of Seibt's Apparatus, forwarded on application. 4973, 1105, 5765. £ s. d. 1. 4.0 1. 2.0 2. 4.0 0. l-'.O 0.12.0 5. 0.0 3.10.0 5. 0.0 1. 6.0 !. Hi. <> 5759, 5763, No. 63269. Seibt's Apparatus. Hertz's Experiments. 1039 63 268 A. 63268, 63269. 63 268 B. 63 268 C. 53,508. Resonance Tube on base, with open ends, but can be closed at one end, £ s. A. Figure 1. 8. 0 5.3,500. Tuning Fork Cj = 256 compound vibrations, with grip 1. 0. 0 53.510. - - idem, c.2 = 512 compound vibrations 0. 18. 0 53.511. - - i d e m, g2 = 768 compound vibrations 0.18.0 Apparatus for the Experiments on Electric Power Rays, after Prof. Heinrich Hertz. (of. Hertz, Untersuchungen iiber die Ausbreitung elektrischer Kraft, Leipzig, 1895, Johann Ambrosius Barth.) 63.267. Apparatus after Grimsehl for repeating Hertz's Fundamental Experiments, Figs. A — C (Grimsehl, Figs. 1057—1059) 3. 0. 0 In these apparatus, as in the original Hertzian Experiments, the secondary spark in the so-call- ed resonator is used as indicator. The induction coil should have a spark about 10 cm long. 63.268. 2 Parabolic Mirrors, one with Hertzian transmitter (oscillator), the other with a coherer (resonator), Figure s, together with a tuned electric bell for signalling, 2 Dry Cells, 1 Wire Grating, 2 Sheet Iron Screens and 1 small Metal Plate for setting the distance of the oscillator balls (Richarz, Neuere Fortschritte auf dem Gebiete der Elek- trizitat, 2nd Edn., pp. 66 — 75), without the induction coil or accumulators illus- trated 4. 0.0 In this set, in which a coherer (Branly Tube) is used as indicator, the following experiments can be made: rectilinear expansion of waves (Fig. A), screening effect, reflection (Fig. B), polarisation (Fig. C). The following paraffin prism No. 63,269 is used for refraction. The induction coil should have a spark-length of not more than 2 — 3 cm. Description and precise directions for use are ap- pended. 63.269. Paraffin Prism, F i g u r e, with board and wood wedges 1. 16. 0 CI. 5879, 5877, 5905, 587R. 1040 Voltaic Electricity. Section 10: Electrical Oscillations. No. 63 270 — 63 270 A. 1:8. 63 270 C. 1:12. 63270D. 1 : 12. 63 270 E. 1 : 10. 63 270 F. 1:8. 63 270 G. 1:12. 63,270. Complete Set for demonstrating all essential Experiments with Hertzian Waves and Wireless Telegraphy, after Weinhold, Figs. A— J (W. D., Figs. 611—619 [556—564]) The apparatus comprises: 1 complete Receiver on marble with metal protecting case, Branly Tube (Coherer), clapper, sensitivity relay, accumulator and dry cell, Fig. A; 1 Transmitter (Vibrator or Radiator) with horizontal spark gap, Fig. B; 2 concave Mirrors with holders, mi hoard, for reflection, etc.; Figs. C and D. 1 plane Glass Mirror for reflection: 1 Stand for the connecting leads, cf. Figs. D and G; 1 Sheet Iron Slab, 1 Board coated with Tinfoil, 1 Wire Net, 1 Glass Plate and Wire Grating flection: 1 Paraffin Prism with pasteboard screen, coated with Tinfoil, and holder, for refraction, Fig. •2 Glass Mirrors for interference, Fig. F; 1 Mirror in frame for polarisation, Fig. G; 1 Mirror with Glass Cup (as lens) in frame, for polarisation, Fig. H; •J Supports: 1 Transmitter for wireless telegraphy, Fig. J. Cl £ s. .1. 16.10.0 variable- for re- E: 6133,6183. 6135,6139,6138. 6134,6137. No. 83277. Hertzian Experiments. 1041 63 270 J. 1:8. 63 270 H. 1:10. 63275. 1 : 5. 63 274 A. 1:4. 63 274 B. 1:5. 63.271. Hertzian Wave Transmitter (Vibrator), after Weinhold, separately, Fig. 63,270 B (W. D., Fig. 613 [558]) 63.272. Transmitter for Wireless Telegraphy after Weinhold, alone, Fig. 63,270 J (W. D., Fig. 619 [564]) 63.273. Branly Tube after Weinhold, separately (W. D., Fig. 611 [556]) 63.274. Complete Exciter for short Waves after Prof. Jagadis Chunder Bose (Ztschr. f. d. phys. u. chem. U. 10, p. 149), Figs. A and B The apparatus consists, as shown in Fig. 63,274 A, of a frame with manipulator, 1 Storage Battery, 1 Induction Coil, 1 Interrupter the knob of which projects above the cover of the apparatus, and one small Radiator in oil vessel with concave copper mirror. The entire device can be placed in a protecting box formed of an iron and a copper sheet metal jacket, Fig. B, thus obviating the influence of magnetic and electric waves on the apparatus. The waves emitted by the radiator can be propagated through the tube inserted in the jacket. The apparatus is ready for use when closed since the interrupter can be operated externally by the push mentioned. The secondary batteries can be cut out by means of the plug visible in Figs. 63,274 A and B. Two double discs can be screwed out of the protecting jacket (Fig. B) in order to be able to observe the two spark gaps. 63.275. 1 Coherer for above, on stand, Figure 61,280. 1 Pointer Galvanometer for above 63,277. 1 Simple Optical Bench and a simple Goniometer for same, with cylindrical lens, 1 plane mirror, 1 cylindrical mirror, 1 prism, 2 half -cylinders, 2 copper wire gratings for polarisation Cl. 4514 0136, 3016 3014. 3015 £ S. d. 0.12.0 1.16.0 0. 6.0 12. 0.0 1. 4.0 2.10.0 9. 0.0 66 1042 Voltaic Electricity. Section 10: Electrical Oscillations. No. 63278 — 63 280. 1 : 18. 63278. 1:18. 63281. 1:18. 63283. 1:10. 63285. 1:3. Large Pattern Apparatus for Hertzian Wave Experiments. £ »• 63.278. 2 Parabolic concave Mirrors after Garbasso, Figure, 0.7 m high, 1.2 m aperture, 0.12 m focal distance, composed of two wood formers and a mimber of well-rounded nickelled sheet iron strips 27 cm long and 5 cm width 4. 10. 0 63.279. - - idem, same size, after Zehnder, of three wood formers and a number of per- pendicular wires, constructed as a wire mirror (Wieden. Ann. d. phys. Vol. 52, 1894, p. 55) 4. 10. 0 63.280. Octagonal Wire Grating in Wood Frame, 0.7x0.7 m, Figure, can be used verti- cally and horizontally, stretched with copper wires 1. 4.0 63.281. Large Pitch Prism, Figure, with refracting angle of 30°, 1.2 m side length and 0.7 m high, composed of three single prisms. Bach prism consists of a wood box into which hard pitch is run in G. IL*. o 63.282. 2 Screens of Sheet Zinc on Wood Frames, 1 m long, 0.7 m high, for reflection experi- ments Each £0.14.0 1. s. o 63.283. Primary Conductor after /Hinder, Figure, on special wood stand with levelling screws (Wied. Ann. d. I'liysik, Vol. 52, 1894, p. 52) 2. 0. 0 The halves of the primary conductor are cylinders made of brass tubing, brass spheres being soldered on one end and simple arched surfaces on the other. The conductor wires are secured 1>\ conical plugs. The primary conductor halve* are enclosed in a pasteboard box having a glass front wall. t'l. 3020,3021,3023, 3022. 3024, 3025. X... 63 287. Hertzian Experiments. Stationary Electric Waves. 1043 63 287. 1 : 8. 63.284. Secondary Conductor after Zehnder, Figure, on wood stand having leivellng £ s. d. screws (Wied. Ann. Vol. 52, 1894, p. 53) 1. 4. 0 63.285. Discharge Tube after Zehnder, Figure 0. 18. 0 The tube has two leads for connecting with the secondary conductor halves and three leads for connecting with the high-voltage accumulator or the shunt current of the induction coil replacing the current of the accumulator (cf. Zehnder, Wied. Ann., Vol. 47, 1892, pp. 77 and 90; Vol. 49, 1893, pp. 549 and 724; Vol. 52, 1894, p. 34). High-voltage Storage Batteries: see p. 856. 63.286. Apparatus for demonstrating and measuring Stationary Electric Waves on Wires after Lecher, Figure (Wied. Ann., Vol. 41, 1890, p. 850), without Lecher tube or induction coil 6. 0. 0 The apparatus consists of two pairs of zinc disc 400 mm diameter, fixed on insulating stand and provided with connecting terminals; two of these discs are capable of motion so as to be able to vary the mutual distance of the discs. At the centre of the baseboard is the spark gap formed of two 30 mm In a^s spheres, 7.5 mm distance apart, these spheres being nickelled and fixed on ebonite pillars. These discharge spheres are in direct connection willi the two fixed zinc discs by wires, and wires 1 mm thick lead from the movable zinc discs to two terminals, on ebonite pillars, at a mutual distance of 300 mm. From here two parallel running wires 9 m long lead to a heavy, adjustable iron pillar stand. Of the two wire clips, provided with ebonite insulating knobs, one is arranged for suspension and for easily sliding along, and the other for fixing by screws. (•>:•!. i>«7. --idem, modified by Weinhold (W. D. Fig. 609 and 610 [554 and 555]), without Lecher tube or induction coil, Figure 2. 10. 0 Cl. 3030. 3580. 66* 1044 Voltaic Electricity. Section 10: Electrical Oscillations. No. 63 288 - 63 288. 1 : 6. 63289. 1:8. 63 291. 1 : 15. 63,288. Lecher Tube for Apparatus Nos. 63,286—63,287 63.289. Apparatus after Walter Biegon von Czudnochowsky, for demonstrating stationary Electric Waves on Wires, Figure; simple pattern (Ztschr. f. d. phys. u. chem. II. 16, 1903, p. 345); without tube or spark coil Two foot terminals No. 60,172 (£ 0. 6. 0 each) and a helium tube No. 63,295 are necessary for the experiments with this apparatus. t 63.290. Exciter for stationary Wire Waves, after Grimsehl (Ztschr. f. d. phys. u. chem. U. 21, 1908, p. 9; Physik. Ztschr. 8, 1907, p. 485) Supplied with the apparatus are: 2 copper wires, wire holder with terminals. 3 bridges and a small helium tube. 63.291. Aron's Tube, Figure, for demonstrating electrical Oscillations (Wied. Ann., 45, p. 553, 1892,) without exciter or induction coil One of the experimental arrangements similar to Lecher's is used. From the secondary zinc plates opposite the exciter plates, at a mutual distance of 30 mm, two 2 mm thick aluminium wires are conducted parallely 3.5 m through the air and 2.5 m through the 60 mm diameter Aron tube, the wire in the tube being of the same length as that outside. The glass tube is connected by a length of tubing with the water air pump and evacuated to a pressure of 10 — 20 mm mercury column. With this arrangement the tube is usually .seen to light up over its entire length in the darkened room. If, however, the free portion of the leads is bridged over, the light is generally extinguished. By sliding the bridge, however, it is possible to generate stationary electric waves so that the tube shows one more or non-luminous nodal points. 63.292. Apparatus after Ooolidge-Blondlot, for demonstrating electric Waves, F i g u r e (Wied. Ann. 67, 1899, p. 578^, consisting of a modified Blondlot Exciter with ebonite protecting jacket, on stand with glass pillar, a Tension Device on stand, 2 Copper Wires cadi 0,2 mm thick and 5.5 m long, and 6 Bridges of different size In this apparatus use is made either of a Lecher Tube at bridge or wires lighting up in vaeuo are employed, but the waves are visible by the luminesence of the wires in free air. In order to obtain as strong oscillations in the secondary circuit of the exciter as is po>-il>]e. the exciter is of the same size as the primary oscillating circuit and is brought as near to it as possible. With a view to attaining this the two circuits are separated simply by mica plates of a total thickness of '2 mm and are contained in an oil bath, thus preventing any sparking over in the secondary. The primary circuit is constructed in two parts, the distance apart being regu'ated by insulating screws fitted on the ebonite cover of the appara.ni- The following are necessary for working the apparatus: 1 Induction Coil of l.">o — 2(Hi mm spark- length; 1 spark Micrometer No. 63,208 or 63,209; 1 High-tension Transformer \o. (i:>.^10 and 1 Leyden Jar No. (ii>..VS-_>. Directions for use sent on application. »>(>. Leyden Jar, height 26 cm, with terminals 63,293. Wavemeter after Drude, with air condenser for determining the period of oscillation and, consequently, the wave-length in the oscillation circuits for wireless telegraphy (I)rudes Annalen, 9, 1902, p. 615), Figure. Without vacuum tube The apparatus consists of a small air condenser with two 1 mm thick parallely stretched copper wires connected to it, these wires being fixed to a wood baseplate -1 m long. An electrodeless vacuum tube is used as indicator. \Vuve-lengths from \~2 to ."><• in can be determined with ease. Cl. 3581.3031. 3n.n. £ s. d. 0. 4.0 2. 0.0 4. 0. 0 1. 16. 0 4. 0. d 1 . 0. 0 5. 0. 0 No. 63301. Stationary electric Waves. 1045 63 292. 1 : 7. 63294. 1:8. 63 293. 1 : 15. 03. 294. Wavemeter after Drude, with oil condenser, especially for determining the duration £ »• «l. of oscillation of wire coils (Drudes Ann., 9, 1902, p. 293), Figure, without helium tube 8. 0. 0 63,294 a. Tesla Transformer with Leyden Jar, after Drude, for above (Drudes Ann., 9, 1902, p. 293) 2. 8. 0 63. 295. Helium Tube for vise with the Drude Wavemeters, Pliicker form with two electrodes 0.15/0 03.296. -- idem, with one electrode j 0. 14. 0 03.297. - - i d e m, without electrode 0. 12. 0 03.298. - - i d e m, cylindrical pattern with one electrode 0. 14. 0 03.299. Apparatus for Measuring the Dielectric Constant of Liquids, after Drude (Wied. Ann., 61, 1897, p. 466) 5. 0. 0 03.300. --id e m, after Schmidt, for determining the Dielectric Constant of Crystals (Drudes Ann., 9, 1902, p. 919) 5. 0. 0 63.301. Model after (iarbasso. for Explaining the Hertzian Resonance Phenomena (Ztschr. t. d. phys. u. chem. U. 15, 1902, p. 331, Fig. 7; Fr. phys. Techn. I, 2, Fig. 3284) . . 13. 0.0 Cl. 3582, 4695. urn;.. 1046 Voltaic Electricity. Section 10: Wireless Telegraphy (Radio-telegraphy). No. 63 302 - 63 302 A. 1:5. 63 302 B. 1:8. 63 305 A. 1 : 7. 63 305 B. 1:7. Wireless Telegraphy (Radio-telegraphy). (a) Apparatus for small-scale Experiments. 63,302. Wireless Telegraphy Demonstration Apparatus, consisting of a Transmitting Station, Fig. A, with radiator and 2 resonators; and a Receiving Station, Fig. B, with coherer. tapper and '2 resonators The apparatus is very efficient -it short distances. The spark is generated either liy a Miiall induction coil of 30 — 50 mm spark length or by an influence machine. One cell is necessary fin- working tin- secondary station. An accurate description i> appended to each apparatus. 63,305. Wireless Telegraphy Demonstration Apparatus, perfected pattern; consisting of a Transmitting Station, Fig. A, with an oscillator having three spark gaps and two reso- nators; and a Receiving Station, Fi]>;n:il us -cut on ;i]>)>lic;ilioii. (I. 3053, 3047, 30.14, 2619. Xo. 63 32;>. Wireless Telegraphy. 1049 63 323 A. 1:13. 63 323 B. 1:13. 63,317. Electric Bell for calling . ...... '. .................. 62.326. Morse Ink Writer, small pattern, cf. Fig. 62,325, p. 959, without cell ...... 62.327. Morse Ink Writer, with clockwork, on polished mahogany board, Figure on p. 959 63,319. - - i d e m, with one bell and two switches combined on one board, Figure. . 61,147. Morse Key, Fig. on p. 868 .......................... 63,323. Complete Wireless Telegraphy Demonstration Apparatus after Prof. Braun, Figs. A and B. without induction coil, -Morse key. Morse wiiter, or cells .......... The transmitting station contains a spark gap, a Leyden jar battery, a transformer, and a mass 2.5 m high with transmitting wire and an anti-capacity for same. The mass is constructed of bamboo, being composed of three parts which can be inserted in each other. The jib at the end of the mass t\v<> pulleys in order to allow of the transmitting wire being drawn up. The receiving station, in addition to containing the mass with the receiving wire and anti- capacity, has an oscillation circuit formed of a condenser and self-induction coil, the coherer, the relay, a bell, the tapper and a small auxiliary condenser. An induction coil having a spark-length of only 30 mm is sufficient to work the apparatus. Complete description is appended to each apparatus. As Morse Writer No. 62,327 can be used or, better still, the following: (>:.'. .".29. Standard Ink Writer, Figure, with detachable spring drum, horizontal paper roll in the base (which can be removed), on polished mahogany socket .......... 62.332. Extra price for Automatic Release, very practical ............... 63,325. Coherer Tester ............................... £ s. d. 0. 4.0 2. 0.0 4. 0.0 5. 0.0 0.10.0 26. 0.0 12.10.0 1.10.0 1. 0.0 Cl. 3049,3049'. 1050 Voltaic Electricity. Section 10: Wireless Telegraphy (Radio-telegraphy). No. 63 326 — 63 326 A. l : r>. 63 326 B. 1:5. 63,326. Complete Wireless Telegraphy Demonstration Apparatus after SLaby-Arco, Figs. A — D, * with aerials as in No. 63,327 21. 0. 0 The Transmitting Station consists of an induction coil with platinum intenupter, adjustable spark gap, 2 Leyden Jars, a variable self-induction coil and a Morse key. The Receiving Station contains a tuning coil, a small condenser, a relay, a coherer, the tapper and a dry cell. Morse Ink Writers, <•!'. Nos. 62,327, 62,329 and 62,332. A complete description of the apparatus forwarded on application. <;:;. .".I1 7. Wireless Telegraphy Demonstration Apparatus, "Telefunken" System; Fig. A, Trans- mitter; Fig. B, Receiver; Fig. C, Transmitter and aerial system; without Morse Writer or Alarm The connections of this apparatus are in exact accordance with the modern method of eon necting up this system, such as employed in the larger Telefunkon plants having high frequency oscillation circuits. The apparatus comprises a complete Transmitting and Receiving Apparatus (without Writer) also two identical aerial systems for transmitting and receiving. The table included in the illustration is not covered by the above price. Description and instruction!, for use on application. Suitable Morse Ink Writers: see under Xos. 62,327, 62,329 and 62,:;.;i'. 23. (i. Cl. 3051, SOW. No. 63330. Wireless Telegraphy. 1051 Spark 0>p --0 O Hammer Interrupter n I *« J Tuning Coil Short Circuited Spark Gap Avnai Diagram of Connections of the Transmitting Station of the Slaby-Arco system. 63 326 C. 63 327 C. 1:20. Tapper BO, Switch I I ells ; , I i «-(k-"4 Diagram of Connections of the Receiving Station of the Slaby-Arco system. 63 326 D. 63 327 A. 1:5. 63 327 B. 1:5. 63 328. 1 : 5. 63.328. Branly Tube, Figure, filled with small iron screws, for demonstration .... 63.329. Automatic Needle Coherer after Bleckrode 63.330. Coherer after Pantenius (Kolbe, Elek.-Lehre, 2nd Edn., Vol. 2, 1905, Fig. 80A) . . Cl. 6598, 65M9, 8583, 3584. 3585, 3870. £ s. d. 0. 16. 0 0. 6.0 1. 4.0 1052 Voltaic Electricity. Section 10: Wireless Telegraphy (Radio- telegraphy). No. 63331 — 63332,63333. 1:7. 63 337. 1 = 3. 63.331. Thermocouple, F i g u r e, after Rubens, can be used MS a Wave Detector .... As galvanometer for above use can be made of an astatic or a moving-coil mirror galvanometer of low resistance and high sensitivity. Valve Tube as Audion (Wave Detector): see under Xo. 63,136, p. 1024. (b) Small-cale Apparatus for Wireless Telegraphy. 63.332. Righi Radiator, Figure, consisting of baseboard and two ebonite pillars on tin- free ends of eaeli of which a brass rod with brass sphere rotates in hinges, together \\ith terminals, but without the accessories illustrated 63.333. Key, Figure, with extra-thick platinum contacts and long ebonite push . . . 63.334. Key, Figure, for heavy currents The key is arranged in such manner that the arc formed on interrupting, and forced upwards by its own heal. is not deleterious to the apparatus. One of the contacts is interchangeable, bi'in.': made of carbon; it must always be connected with the positive pole of the current lead. The key. which is specially adapted for working induct inn coils having Wehnelt Interrupter, is nl extraordinary resisting powers as constructed. 63.335. Morse Key for currents to 50 amperes. Figure, with thick platinum contacts and electromagnetic spark extinguisher The key is intended for heavy currents as produced when working the induction coil with the \Velmeli break. 63.336. Adjustable Steel Coherer, with filling material £ s. d. 1. 0. 0 2. 0. 0 "2. -2. 0 1.12.0 63.337. Device for Clipping and Shaking the Coherer, Figure, suitable for Cohere] No. 63,336. Price without Coherer 63.338. Round pattern polarised Relay, Figure, having resistance of approx. 7,0(10 ohms, with four polarising cells for preventing sparking ( -1. 4675. 3058, 3055. 6171. 8. 0.0 1. 6.0 3. 10. 0 9. 0.0 3059. No. 63 348. Wireless Telegraphy. 1053 MAX KQHL CHEMMTZ 63 338. 1 : .->. 63 341. 1 : 10. 63 340. 1:10. 63 345. 1 : 4. 63,3:59. Round Relay No. 63,3.38, Coherer No. 63,336, and Shaking Device No. 63,337, mounted together on one polished mahogany slab, with all leads and the necessary terminals Standard Ink Writers: see Nos. 62,329/32, p. 1049. 63.340. Assembled Receiving Station, Figure, comprising 1 adjustable steel Coherer No. 63,336, 1 clip and shaking device No. 63,337 for same, 1 round pattern polarised relay No. 63,338, and 1 standard ink writer No. 62,329 with automatic release No. 62,332, mounted together on one polished mahogany board 63.341. Magnetic Detector after Marconi, Figure, complete with telephone and 110 Volt D. C. motor This apparatus is splendidly adapted for demonstrations. If a motor for different voltage or current is desired, this should be stated when ordering. 63.345. Zickler Tube for opto-electric Telegraphy, Figure, with quartz plate and adjustable quartz lens (Ztschr. f. d. phys. u. chem. U. 12, 1899, p. 43; E. T. Z., 1898, pp. 474 and 487) Opto-electric Telegraphy by Zickler's method is based on the phenomenon of a spark gap allowing i he sparks to pass when submitted to radiation from ultra-violet light, the sparking ceasing, however, when radiation is stopped. The spark gap is enclosed in an evacuated glass tube having a quartz window at one end ; in front of this window is fitted a sliding, convex, quartz lens which condenses the ultra-violet rays on the cathode. The ultra-violet rays are shut off by inserting a thick glass plate in the luminous pencil of the arc lamp. As to the source of light to use, an electric arc lamp (say, that of a projection lantern), the condenser of which has been removed, is sufficient for demonstration purposes. For condensing the light on the tube it is advisable to use the following quartz lens when the distance in question is somewhat large. 63.346. Quartz Lens 38 mm diameter 63.347. Glass Plate, 200x150x8 mm £ s. d. 15. 0.0 29. 10. 0 11. 0.0 3. 0.0 0. 12. 0 0. 3.0 63,348. Geissler Tube for Zickler's opto-electric Telegraphy 0. 3. 0 The Geissler tube is put in series with the induction coil and spark gap. While the Geissler Tube only gives a dull glow when there is no sparking over in the Zickler tube, it lights up much brighter with the passage of sparks. Cl. 2623, 3048, 3057.3061. 1054 Voltaic Electricity. Section 11 : Telephony and Microphony. No. 63360 — 53 587 B. 1:4. 53 587 A. 1 = 4. 63 360. 1 : 7. 63362. 1:4. 63 369. 1 : 4. Section 11: Telephony and Microphony. 53,587. Telephone after Ph. Beis, consisting of transmitter, Fig. 53.587 A, and Eeceiver, Fig. 53,587B Between transmitter and receiver — called by Reis himself the reproducing apparatus — a bat in y is so connected up that the two are traversed in series by the current. The latter should be of such strength that the armature of the small magnet on the transmitter is attracted; for this purpose 3 — 4 Bunsen cells or storage cells should suffice, according to the distance between both stations. 63.360. Apparatus for Explaining the Working of the Telephone, Figure (Ztschr. f. d. phys. u. chem. IT. 2, p. 133; Kolbe, Einf. i. d. Elektrizitatslehre, Vol. 2, Fig. 78 A) The apparatus consists of two powerful bar magnets on to which two wire coils are slipped; the coils are connected with each other. In front of one of the magnets a small iron piece is suspended so as to be capable of oscillation. If the thick iron plate given in with the apparatus is brought up to the other magnet at regular intervals (say, to the beat of the pendulum oscillation) until it makes contact, and is then removed, the small iron piece in front of the first magnet is set into oscillatory motion, which can be increased until the iron piece is finally attracted by the magnet. 63.361. Telephone in Glass Case. Figure, with ebonite mountings; all internal parts quite visible ' 63.362. Telephone after Bell, Figure, in ebonite sheath with double flexible 63,367. Round Pattern Telephone, F i g u r e, double-pole, with niekelled cap, ebonite mouth- niece and twin flexible 63.369. Receiver with lateral ear-piece, F i g u i e, with horse-shoe magnet, niekelled di.i- plintgm case, ebonite piece and twin flexible 63.370. Precision Telephone, Figure, thoroughly well constructed 63.373. 20 metres Twin Flexible, with wire ends for connecting up two telephones . . 63.374. Microphone after Weiuho'd, simple, Figure (W. I). Fig. 600 [549J) 63.375. Microphone after Hughes. Figure (M. P., eparate r us ( l>iivctor'~ room and porter's dwelling). Except for the wire material (No. ti2.:t.~>»i. p. mil) and the cells, nothing further is necessary. The erecting can be dune without special preliminary knowledge. C'l. 3080, 79 K. 80 F, 6011. No. 63389. Telephony. Telephonograph. Speaking Arc Lamp. 1057 63 384 A. 63 384 B. 63.383. Telephonograph after Poulsen, for permanently fixing and conveniently repeating a £ s. d. telephonic conversation, Figure (cf. E. T. Z., 1901, p. 57, 181; Drudes Annalen d. Physik, 3, 1900, p. 754), with microphone for transmitting, two telephones for receiving, and the necessary cells, also two steel discs and demagnetizing device 11. 0. 0 The fluctuations in a current produced by a microphone are carried through a magnetizing coil, which is guided over a hardened steel plate in a spiral line, in a similar manner as employed in gramophones. The fluctuations in magnetization of the steel plate which are permanently recorded, suffice to induce currents in the coil of the magnet when the latter is again guided over the steel plate, these currents giving in the telephone an accurate and surprisingly plain reproduction — which can be repeated at will — of the sounds originally conducted into the microphone. 63.384. Demonstration Apparatus for Wireless Telegraphy with electric Waves, consisting of a Transmitting Station, Fig. A, and a Receiving Station, Fig. B, for single direction working 27. 10. 0 Direct Current at 220 volts is necessary for working. Complete description sent on application. • 63.385. - - idem, consisting of two stations which can both transmit and receive, for reci- procal working 37. 10. 0 Complete Apparatus for Experiments with the Speaking Arc Lamp, Figure on p. 1058, consisting of: 50,892. Arc Light Hand Regulator (D. C. of at least 80 volts and 10 amps is necessary) . i 2. 2.0 63.386. Series Resistance for the Arc Lamp, for connecting to 110 — 120 Volts 0. 18. 0 Or: 63.387. Series Resistance for the Arc Lamp for connecting to 220 volts 2. 0. 0 63.388. Self-induction Coil 2. 10. 0 63.389. Microphone with Switch and Eegulating Eesistance 2. 0. 0 Cl. 81AF, 81BP. 67 1058 Voltaic Electricity. Section 11: Telephony and Microphony. No. 63 390 — 63 395, 50 892, 63 386, 63 388, 63 389. 1 : 8. Complete Apparatus for Experiments with the Speaking Arc Lamp after Weinhold (W. D., £ «• .<> On rotating, heating in the cylinder takes place by the friction of the spring, the friction causing a current, which flows from iron to German silver or vice-versa according to the position of the spring. 63.416. Needle-shaped Thermocouple, Figure (M. P., 9lh Edn., Ill, Fig. 825), for intro- ducing into plant and animal tissues 0. 10. 0 63.417. Thermocouple, F i g u r e, after Friedr. C. G. Miiller (M. T., Fig. 234), of iron and constantan 0. 8. 0 63.418. Thermo-cell, F i g u r e, after Friedr. C. G. Muller (M. T., Fig. 233) 0. 1. 8 63.419. Thermo-pile after Melloni, Figure, Demonstration Model, with three bismuth- antimony cells on stand, with two terminals 0.18.0 63.420. Apparatus for Determining Temperature with Thermocouple, Figure (\V. u. E. phys. I'rakt., 4th Edn., Fig. 327), with adjustable stand, L> baths and 2 thermometers L'. 10. 0 The thermocouples consist of an approx. 3 mm thick German silver wire which at a and \> resper- tively is soldered to a copper wire of same thickness; glass tubes are slipped over the vertical ends of these copper wires at a and b and reach to the junctions. The junctions themselves are immersed in reagent glasses Tilled with paraffin oil or petroleum. The sheet iron vessels are filled with water and are provided with thermometers. Cl. 3883, Thermo-piles for Charging Accumulators: see p. s.v.i 680.3006,4522, Thermo-piles for Shewing Thermal Differences: see Section "Heat". 2098, 3097. N7o. 63 431 Thermo-electricity. 1063 63 428. 1 : 5. 63 422. 1 : 5. 63425. 1:11. 63 441. 1 : 7. Noe's Thermopiles, Figure (M. P., 9th Edn., Ill, Fig. 835), the e. m. f. of a cell is approx. 0.06 volt, that of a pile of 25 cells, for example, equalling 1.5 volt: List No. 63,421 63,422 63,423 Number of Cells 12 20 25 £ 0.15.0 1.4.0 1.10.0 63.424. - - idem, larger model, with 25 cells These thermo-piles have the cells arranged star-shaped and are supplied without heating device. They can be heated with any Bunsen Burner or spirit lamp. 63.425. 2 Thermopiles after Noe, consisting of 20 cells each, with 2 spirit Bunsen burners, >'ii (SUV Thermopiles for Demonstration Purposes, Figure: Number of Cells 26 38 50 50 Tension, approx. volts 1.8—2.2 2.8—3.2 3.8—4.2 4.0 — 4.5 On Short Circuit, approx. amps. 3—4 3—4 3 — 4 4—5 List No. 63,426 63,427 63,428 63,429 With Gas Burner £ 1.2.0 1. 13. 0 2.5.0 3.0.0 List No. 63,430 63,431 63,432 63,433 With Spirit Burner £ 1.8.0 1. 19. 0 2. 13. 0 3. 10. 0 Thermopiles Nos. 63,421 — 63,434 are used for demonstrating the practical arrangement of thermo- piles; they are not intended for the permanent charging of accumulators. They are capable of giving for a short time quite appreciable outputs. 63.440. Thermo-electric Cross after Peltier (M. P., 9th Edn., Ill, Fig. 839), for showing the generation of cold by the electric current 63.441. Apparatus for Peltier's Experiment after Weinhold, Figure (W. D., Fig. 620 [565]) 2. 5.0 5.10.0 1. 0.0 0.16.0 Cl. 6554, 3517,3104,5327. 1064 Section 12: Thermo-electricity. Miscellanea. No. 63 442 — 63 445. 63 443. 1 : 4. 63 446. 63 442. 1 : 6. 63447. 63.442. Electrothermic Apparatus after Schumann, Figure (M. P., 9th Edn., Ill, Fig. 842) Bismuth rods are soldered on to both sides of an antimony rod. The junctions are enclosed in the bulbs of two air thermometers, so that the Joule effect is produced in both bulbs in the same manner, but the Peltier effect in the opposite manner. The liquid pointer gives opposite deflections when opposite currents are conducted through. 63.443. — idem, smaller, Figure, for objective projection The tubes with the liquid indicators are fitted in front of a transparent scale in order to render the phenomenon simultaneously visible to all the audience. The Peltier Effect can also be shewn with the Kolbe Differential and Double Thermoscope (see "Heat" Section). 63.444. Thermocouple after Wunder (Ztschr. f. d. phys. u. chem. U., 24, 1911), Figure on p. 1065. The current density produced by heating the thermocouple is sufficient to allow the magnet to carry an armature Mathematical Instruction Models. 63.445. Model after Meffert, for Explaining the Pythagorean Theorem, Figure 63.446. — idem, different pattern, Figure 63,447. - - i d e m, for proving the theorem that the areas of like polygons are as the squares of homlogous sides, Figure Mineralogy. 100 Minerals, selected pieces, carefully chosen and arranged in compartment s : List Xo. 63,452 63,453 Average Size of the Minerals, cm 5x6 7x9 £ 2.10.0 4.5.0 The collection comprises: I. Elements: Graphite, Sulphur, Bismuth, Copper. II. Sulphides: Real- gar, Antimonite, Native molybdenum-sulphide, Galena, Cinnabar, Zinc blende, Magnetic Pyrites, Red Nickel Pyrites, Pyrite, Marcasite, Grey cobalt-ore, Arsenical Pyrites, Copper Pyrites, Fahlerz. m. Oxides: Rock Crystal, Smoky Quartz, Amethyst, Quartz, Agate, Flint, Zirconium, Rutil, Tin Stone, Pyrolusite, Psilomelane, Corundum, Emery, Iron-glance, Red Iron-stone Titanic Iron, Opal, Brown Iron-stone. IV. Haloid Salts: Rock Salt, Fluorspar, Cryolite. Carnallite. V. Ahuninates, Ferrites, Borates: Spinel, Magnetic Iron Ore, Boracite. VI. Nitrates, Carbonates: Sodium Nitrate, ('ale-spar (crystallised), Calc- spar (cleavage piece), Dolomite Spar, Magnesite, Zinc-spar, Iron-spar. Aragonite, Strontianite, Cerussite, Amalachite. VH. Sulphates, Tugstates: Anhydrite, Heavy Spar. Cnele-iin. Lead Snlphte. <;ypsum, Ala- baster, Alunite, Seheelite, Wolframite. Vlll. Phosphates: Apatite, Phosphorite, Pyromorphite. IX. Sili- cates: Cyanite, Topaz, Staurolite, Tourmaline, Kpidote, Vesuvian. Garnet, Olivin. Bronzite, Augite, Actinolite, Hornblende. Nepheline. Xosean, Leucite, Orthoclase, Sanidin, Microglin. Albite, Oligoclase, Labradorite, Natrolite, Desmine, Chabasite, Biotite, Muscovite, chlorite. Serpentine, Talc, Kaolinite. X. Organic Compounds: Ozokerite. Asphalt, Anthracite, Coal. This collection mav l>e subject to slight variation acconlini; to our stock of good pieces. d. £ s. d. 2. 0.0 1.12.0 1. 0.0 0. 18. 0 0.15.0 0. 8.0 6154, 408, 5152, 3109, 5153. No. 63 463. Minerals. 1065 63 444. 63462 — 63463. 7x9 cm 63,461 24. 0. 0 63,463 28. 0. 0 100 Minerals in lacquered wood box, with compartments: List No. 63,455 63,456 Average Size of Minerals, cm 5x6 7x9 £ 3. 5. 0 5. 10. 0 100 Minerals in finely polished wood box, with compartments: List No. 63,458 63,459 Average Size of Minerals, cm 5x6 7x9 £ 4. 0. 0 6. 0. 0 250 Minerals, collection for teaching purposes, Figure, the most important samples being good and instructive specimens. Of the crystallised minerals stages or crystals are selected which show plainly the characteristic crystallic shapes. ( Average Size 5x7 Without Box { Ligt ^ 63 46Q £ 15.0.0 In nice stained oak cabinet, with 5 drawers and ( List No. 63,462 small cardboard boxes, Figure . . . . \ £ 18. 10. 0 I. Elements: Diamond, Graphite, Crystallised and heavy; Arsenic, Bismuth, Gold, Silver (wire and sheet form), Copper. II. Sulphides: Realgar, Orpiment, Antimonite, Molybdenum-glance, Galena, Crystallised, hexahedral and massive, Silver-glance, Copper-glance, Cinnahar, Zinc-blende, crystallised and compact, Fibrous-blende, Magnetic Pyrites, Millerite, Red-Nickel Pyrites, Pyrite, hexahedral and pyrito-hedral crystallised, Cobalt-glance, Grey cobalt ore, Marcasite, Arsenical Pyrites, Copper Pyrites, crystallised and compact ; Variegated Copper ore, Antimony - silver - blende, Fahlerz. in. Oxides: Rock Crystal, Smoky Quartz, Amethyst, Common Quartz, Cat's Eye, Tiger's Eye, Ferruginous Quartz, Rose-quartz, Chalcedony, Agate, Jasper, Silicious Schist, Flint, Tridymite, Zircon, Rutile, Anatase, Tin Stone, Pyrolusite, Psilomelane, Wad, Braunite, Hausmannite, Red copper ore, Red tin-ore, Corundum, cryst. and Emery, Iron-glance, Red iron-stone, Red Hematite and Titanic Iron, Hyalite, Opal, Silica, Bauxite, Goethite, Lepidokrokite, Brown iron-ore, Kidney ore, Manganite. IV. Haloid Salts: Sylvine, Rock-salt, cleavage-piece and compact, Fluorspar, hexahed. cryst., octohed. cryst., and cleavage-piece; Cryolite, Carnallite, Kainite, Atacamite. V. Aluminates, Ferrites, Borates: Spinell, rare, blue and black, Franklinite, Magnetic iron-ore, octahed. cryst., duodecahed. cryst. and compact (attractor); Chrysoberyll, Boracite, Tinkal. VI. Nitrates, Carbonates: Sodium nitrate, Calc- spar, rhoinbohed., scalenohed. prismat. cryst., cleavage-piece and double spar, Marble, Compact Lime, Calc-tuff, Chalk, Dolomite-spar, Magnesite, Zink-spar, Iron-spar, Sphaerosiderite, Carbonaceons Iron- stone, Manganese-spar, Aragonite, chisel-shaped, acute pyramidal and triplet, Witherite, Strontionite, Cerussite, Malachite, Vitreons Copper. VEL Sulphates, Chromates, Molybdates, Tungstates, Uranates: Glauberite, Anhydrite, Heavy spar, col. cryst., white cryst. and compact; Coelestine, Lead Sulphate, Gypsum, cryst. and cleavage-piece; Fibreous Gypsum, Alabaster, Alunite, Copper Sulphate (blue Cop- peras), Red lead-ore, Scheelite, Wulfenite, Wolframite, Uranium-pitch ore. Vlll. Phosphates, Arseniates: Monazite, Apatite, brown cryst., transp. cryst. and compact, Phosphorite, Staffelite, Pyromorphite, brown and green; Pharmakolite, Cobalt-bloom (earthy), Wavellite, Kallaite. IX. Silicates. Titanates: Andalusite, Chiastolite, Disthene, Rhaetizite, Topaz, Staurolite, Datolite, Tourmaline, black and red; Axinite, Zoisite, Epidote, Vesuvian, Hessonite, common Granite, Melanite, Syrope, Almandine, Cor- dierite, Beryl, Olivine, Silicious Zinc-ore, Dioptose, Chondrodite, Bronzite, Hypersthene, Wollastonite, Diopside, Diallag, Augite (common cryst. and basaltic), Omphacite, Rhodonite, Anthophyllite, Tremolite, Actinolite, Asbestos, Hornblende, comm. cryst. and basaltic, Glaukophane, Scapolite, Melilite, Nepheline, Sodalite, Noseane, Hanyne, Lapis-lazuli, Leucite, Adular, Orthoclase, Karlsbad twins, Baveno Twin, cleavage-piece and iridescent, Sonadin, Mikroline, Albite, Perikline, Oligoclase, Labradorite, Anorthite, Apophyllite, Analcim, Natrolite, Prehnite, Stilbite, Desmine, Phillipsite, Chabosite, Biotite, Phlogopite, Zinnwaldite, Lepidolite, Muscovite, Paragonite, Ottrelite, Chorite, Serpentine, rare and common, Meer- schaum, Talc, Kaolinite, Pyrophyllite, Bolus, Sphene, green cryst. and brown (Titanite). X. Organic Compounds: Mellite, Petroleum, Ozokerite, Amber, Asphalt, Anthracite, Coal, Brown-coal, Lignite, Peat. In addition we supply any other desired collection of minerals: Prices on application. £ s. d. Cl. 5068, 3592. 1066 Section 12: Miscellanea. Xo 63 472 — bt ,c, = Octohedron. Tesseral System. 63 472 B. 63 472 A. 1:8. a2. I),, c, = Pointed quadrate Pyramid (21'). 63 472 C. :\0. b,, c, = Obtuse quadrate Pyramid (P). 63 472 D. = Obtuse Rhombic Pyramid. 63 472 F. = Aciltr Rhombic Pyramid. 63 472 E. c, (inclined for- ward) = Acute mono ?li lie [Pyramid. 63 472 G. c, (inclined for- ward)^ Obtuse mono:linic Pyramid. 63 472 H. "2- ''i- ''2 (&11 axes inclined towards each other) = Acute triclinia Pyramid. 63J472J. a,, b,, c,, d = hexagonal Pyramid. 63 472 K. 63,472. Axial Cross after Nestler, Figs. A — K, for demonstrating the fundamental forms £. s. d. of all six crystal systems (octohedra and pyramids) 1. 6. 0 All the axial halves consist of two tubes which telescope in each other and which can be firmly clamped in different positions by a spring on the outer tube engaging in notches in the inner tube. Elastics are drawn through the ends of the axes representing the edges of the pyramids. Some examples are shewn in Figs. 63,4728 — 63,472 K. In these the vertical axis is designated by a, the others by b, c and d; and the individual rest-points of the vertical axis — reckoned from the central point — are designated by 0, 1, 2, 3, and those of the other axes by 1, 2, 3. Collection of Copies of Precious Stones, Figure, ideal crystallization forms, imitated in shape and colour, approx. 25 mm in size. Number of Stones . 12 24 36 50 60 88 In Cardboard / List No. 63,473 Box ... I £ 0. 14. 0 In Case . f List No. 63,479 I £ 1.0.0 63,474 1.4.0 63,475 1. 12. 0 63476 2.6.0 63,477 2. 12. 0 63,478 3. 15. 0 63,480 1. 16. 0 63,481 2. 10. 0 63,482 3.8.0 63,483 4.0.0 63,484 6.0.0 63,485. 4 Diamond Copies, in rase, containing, Koh-i- Noor as iv-cut. Keireiit. Florentine, Orloff, cf. Fig. 63,486 <>. Hi. 0 63,486. 9 Diamond Copies in case, F i g u r e, as follows: Saucy, Hope. Koh-i- Nuor as re-cut. Great Mogul, Florentine, liegent, Southern Star, Koh-i- Noor as originally cut, Orloff 1. 6. 0 Cl. 3140. 3141, 3142, 3139,3143.3144. 3147,3148,3145,3148. No. 6350.5. Minerals. 1067 63 480. 1 : 3. 63 486. 1 : 3. 63 489. 1 : 5. 63 499. 1 : 7. 63,487 12 Diamond Copies, the same as No. 63,486, together with Nassack, Pigott and £ s. d. Pascha of Egypt 1. 10. 0 63.488. 15 Diamond Copies, the same as under Nos. 63,486 — 63,487, together with Shah, Kaiserin Eugenie, Polar Star 1. 12. 0 63.489. 22 Diamond Copies, the same as under Nos. 63,486 — 63,488, Figure together with Green Diamond of Dresden, Tiffany, Stewart, Diamant des Herrn (Dresden), Este, Star of South Africa, Jubilee ' 2. 8. 0 Crystal Models of cut crystal glass, 30 — 70 mm in size, Figure: No. of Specimens C 12 20 30 40 60 In Card- (List No. 63,490 63,491 63,492 63,493 63,494 63,495 72 90 board Box \ £ 0. 10. 0 0. 18. 0 1. 10. 0 2. 0. 0 63,496 63,497 2.12.0 3.15.0 4.10.0 5.10.0 Tnp fListNo. 63,498 63,499 63,500 63,501 63,502 63,503 63,504 63,505 e\ £ 0. 18. 0 1. 14. 0 2. 8. 0 3. 4. 0 4. 2. 0 6. 10. 0 7. 10. 0 9. 0. 0 <'l. 3593, 3595, 3596, 3597. 1068 Section 12: Miscellanea. No. 63 507 — 63 507 A. 1:3. 63507B. 1:3. 63531. 1:5. 63.507. 15 Models of Crystals^composed of glass discs, with enclosed base of cardboard, £ s. d. Fig. 63,507 A or with axes of coloured threads, Fig. 63,507 B, well mounted and cemented; size of the single crystals 15 — 25 cm 2. 10. 0 The collection contains the most important fundamental shapes. 63.508. 16 Models of Crystals, of glass, for demonstrating simple combinations of holohedrie and hemihedric forms, the combinations of pasteboard, enclosed 4. 15. 0 63.509. 30 Models of Crystals, of glass, with coloured axes drawn in, representing the simple fundamental forms, cf. Fig. 63 507 B, 15 — 25 cm in size 6. 0. 0 63.515. 10 Models of Crystals shewing the most important Intersecting Doublets; the various single crystal individuals fitted by glass of different tint for demonstration, 15 — 25 cm in size 4. o. <> Prices on application for other collections. 63.516. 30 Models of Crystals, of Wood, representing the simple main forms, 5 cm average sixe 1. 10. 0 63.517. -- idem, average size 10 cm 3.15.0 63.518. 30 Wood Crystal Models, large, light construction, for demonstration purposes, the simple main forms, of pear-tree wood, hollow, size 20 — 25 cm r». 0. 0 63.520. 50 Wood Crystal Models, specially collected for High Schools and Colleges, including in addition to the chief types, different combinations and doublets, average sixe ."> em _. Id. <> 63.521. --idem, average size 10 cm (J. !.'>.<) 63.522. 80 Wood Crystal Models, 5 cm in size, after Prof. C. Hintze 5. 0. 0 63.523. - - idem, size 10 cm 14. 5. 0 a. 3150, sir.i, 8168. No. 63 536. Cristal Models. Anatomical Models. 1069 63 532. 1 : 5. 63534. 1:10. 63 536. 1 : 3. 63535. 1:1. 63.524. 150 Wood Crystal Models, size 5 cm, after Prof. C. Hintze 63.525. — idem, size 10 cm 52,227. Hardness Scale after Mobs, Fig. 52,227, p. 312, with large stone specimens, porcelain slab, diamond style, and bar magnet, in wood box 63.531. Blow-pipe Set, Figure, with blow-pipe having pierced platinum point, forceps platinum sheet, 6 platinum wires and 10 reagents Microscopes for Observing Liquid Crystals after Lehmann: see pp. 183 and 536 of this list. Anatomical Models, of Clay Paste and Painted true to Nature. We supply all Anatomical Models, and shall be glad to quote to requirements. The following are a few examples. I. Large-scale Sectional Models. 63.532. Heart, the front wall of which should be lifted off so as to render the four cavities with their openings and valves visible simultaneously, Figure . ' 63.533. - - idem, smaller pattern , II. Actual size Specimens. 63.534. Torso, Figure, with the thoracic and abdominal viscera 63.535. Tongue, Figure, can be taken to pieces , 63.536. Urinary Organs, Figure, can be taken apart £ s. d. 9.15.0 28.15.0 0.18.0 1. 4.0 0. 15. 0 0.10.0 3.10.0 0. 7.0 0.13.0 Ear, Larynx, and Eye Models: see "Acoustics" and "Optics" Sections. Cl. 3164,3167, 317-2, 3171. 1070 Section 12: Miscellanea. No. 63 550 — 63 550. 1 : 6. Cocon I Cocon [Cocon Cocon Cocon 63 554. 1 : 7. 63551. 1:4. 63 553. 1 : 20. 63555. 1 : 4. 63552. 1 : 4. Cl. 3158, 3162, :;i.-iii. :U61.3lG:;, 3160, No. 63 556. Miscellanea. 1071 63556. 1 : 14. p r~ 1 n we oii|j|jiy Philosophical Preparations and Human and Animal Skeletons of the best quality and shall be glad to send separate lists of these if desired. Figs. 63550 — 63555 shew a few examples." Iron Museum Cupboard (Fig. 63556) L Cl. 5011. 1072 Appendix. No. 63 560 — APPENDIX. 63 561. 1 : 7. 63 566. 1 : 8. 63 569. 1 : 63 570 G. 63.560. Pendulum Dynmeter after Friedr. C. G. Miiller, improved type (Ztschr. f. d. phys. u. chem. U., 23, 1910, p. 17), with two bar magnets 100x12x8 mm with agate cap . 63.561. Influence Machine after Topler with 20 rotating discs 300 mm diameter, Figure, for motor drive (M. P., 9th Edn., Ill, Fig. 161) 63.562. Self-exciting Influence Machine after Wimshurst, with double rotation, with two glass discs 90 cm diameter, cf. Fig. 60,442, p. 820, with glass case, without table or the other accessories illustrated 63.563. - - idem, with 4 glass discs 90 cm diameter 63.564. Machine us No. 63,562, but without glass case 63.565. Machine as No. 63,563, but without glass case 63.566. Leyden Jar Battery with two jars 40 cm high in parallel, Figure 63.567. - - idem, with two jars 60 cm high 63.568. - - idem, with two jars 80 cm high 63.569. Condenser after Cavendish, Figure, with three brass plates and a plate each of ebonite, glass, resin, and paraffin wax £ s. d. 4.10.0 32. 0. 0 24. 10. 0 41. 0.0 IS. 10. 0 35. 0. 0 2. 0. 0 3. 0.0 4. 0.0 10. 0. 0 Cl. 5950, 2980, 6174, 6897. No. 63589 Miscellanea. School Experiments with Rb'ntgen Rays. 1073 63 585. 1 : 9. Sliding Resistances, patterns A — F, p. 869, are if specially ordered, supplied also arranged vertically in accordance with Fig 63,570 G, and with one or two contact brushes. The latter arrangement permits of numerous adaptations as shunt resistance. Extra Price for vortical arrangement, cf. Fig. 63 560 G, with one contact brush: Pattern List No. £ A 63,570 0.3.0 B 63,571 0.3.8 - idem, with two contact brushes : List No. 63,576 63,577 £ 0. 8. 0 0. 8. 8 C 63,572 0.4.8 63,578 0.9.8 D 63,573 0.4.8 63,579 0. 10. 8 E 63,574 0.5.0 63,580 0. 11. 0 F 63,575 0.5.0 63,581 0. 12. 8 63.582. Cathode Ray Tube after F. Braun, cf. Figure 61,499, p. 898, with osmose regeneration Since the tubes, in a similar manner to the Rontgen tubes, become harder in use, it is advisable to fit the regenerating device, which permits of introducing gas into the i_iterior. 63.583. - - idem, larger, 1 m long, with screen 130 mm diameter, cf. Fig. 61,500, p. 898, with osmose regeneration 63.584. - - idem, after Braun-Wehnelt, cf. Fig. 61,501, p. 898, with osmose regene- ration 63.585. Switchboard for Accumulators, Figure, specially adapted for electro-chemical purposes, for connecting to pressures up to 16 volts and currents to 20 amps. . . . The switchboard, of marble with wood frame, contains: 1 precision voltmeter 25 volts, 1 volt- meter switch, 1 precision ammeter 20 amps., 1 main switch, 1 stepped sliding resistance permitting regulation in fine steps and over a wide range, also 1 terminals. Apparatus for School Experiments with Rontgen Rays. (Cf. in this connection our complete Introduction, sent on request.) Induction Coils with Accessories, X-ray Tubes, Fluorescent Screens: see pp. 978 — 986. 62,730. Carton with Strips of various Metals, also Glass 63.586. Carton with a Glass Strip 6 mm thick and an Aluminium Sheet Strip 0.5 mm thick 63.587. Fluorescent Screen, size 8x16 cm 63.588. Phalanges in Glass Tube after Weinhold, fqr shewing that X-rays do not undergo any appreciable refraction or reflection (W. D., p. 875) 63.589. Metal Disc with Insulating Grip, for shewing ionisation of the air (cf. Fig. 4 of the Introduction) Cf. in this connection also Nos. 62,731/2, p. 986. CL G20S. £ s. d. 1. 8.0 3. 8.0 2. 3.0 9. 0.0 0. 10. 0 0. 4.0 0. 4.0 0. 6.0 0. 6.0 1074 Appendix. Nr. 63 590 - 63 604. 63 602. 1 : 7. 63 604. 1 : 6. Dry Plates, specially manufactured for X-ray purposes, each plate packed twice in light tight paper: List No. 63,590 63,591 63,592 63,593 Size, cm 9x12 13x18 18x24 24x30 Per dozen, £ 0. 2. 8 0. 4. 5 0. 8. 5 0. 14. 5 "Rapidfolien", extremely active, grainless, intensifying screens for radiographic work: List No. 63,594 63,595 63,596 63,597 Size, cm 9x12 13x18 18x24 24x30 Each, £ 0.10.0 0.18.0 1.10.0 2.6.0 The "Rapidfolien'' reduce the time of exposure to from Vso"1 to Vzo"1 the time ordinarily necessary. They are specially recommended for use with influence machines and small spark coils. X-ray Negatives, original photos of the Human Body: List No. 63,598 63,599 63,600 63,601 Plate Size cm 13x18 Object Hand 18 X 24 Knee, Foot or Shoulder 24x30 Skull 30x40 Thorax 63,602. Rontgen Show Case, desk form, for observing Negatives, Figure, with glow lamp, for plates 24 x 30 cm 63.603. — idem, for plates to 30x40 cm, with two glow lamps Voltage of lamps should be given, or otherwise the Show Cases are supplied for 110 volts. 63.604. Thermopile after Indrikson, Figure (Kolbe-Skellon, Introduction to Electri- city, Part II, Fig. 141 C) £ s. d. 0. 8.0 0. 10. 0 0. 12. 0 0. 18. 0 1. 10. 0 2. 0.0 2. 0.0 ci. tioii. UTS. Estimates of Cost for Physical Apparatus. 1075 Estimates of Cost for Physical Apparatus. For estimates as to equipments for Physical and Chemical Lecture Booms, Preparation Boom, Museums, Students' Workrooms, compiled with due consideration to the means available, and which generally include a lecture table: see pp. 99 — 106 (Vol. I). For estimates as to Projection Lanterns and Accessories: see pp. 189 and 190. Estimates as to Kohl's Megadiascope (Universal Projection Apparatus) and special fittings: see p. 1230 (sewn in after p. 192, Vol. I). Table of prices of Physical Apparatus for projection purposes: see pp. 1094 — 1096, which supersede pp. 190 — 192 in Vol. I. It is assumed in the following collection of estimates that the requisite fittings are at hand, and especially the necessary museum cupboards for the apparatus, a connection to a gas lead and an electric lead supplied with D. C., including for the latter a suitable experimental switchboard, also a projection apparatus together with projection screen and a window obscuring device. Attention should be paid to the fact that in the case of platinum objects or apparatus in which the use of platinum essentially influences the price, the prices will undergo variation with any change in the price of platinum. Estimates Nos. 1—4. Collections of Apparatus in accordance with Standard Requirements. The Standard List (Normalverzeichnis) was presented and accepted at the Fifth General Meeting of the Society for Promoting Instruction in Mathematics and the Natural Sciences, Elber- feld, Autumn 1896 (see also Unterrichtsblatter fur Mathematik und Naturwissenschaften, 2, 1896, page 24). The Collections of Apparatus included in the following pages each form an entire whole; they can, however, should the full amount not at once be available, be installed little by little in such manner that the apparatus of Collection 1 included in the column "1st Acquirement" should be ordered first, while, in a similar manner, the apparatus given under "2nd Acquirement" should be ordered additionally in the following or in a number of successive school years. If, however, the apparatus for each branch of Physics are desired complete at the outset, the apparatus for the various branches can be ordered successively. The numbers given in special columns refer to the "Standard List" mentioned above. The order is, however, kept in accordance with the present Price List. In perusing the estimates it should be noted that only such apparatus pertain to a collection in which the price is inserted in the corresponding price column. Price Lists containing only these apparatus can be obtained from us. Collection 1 in addition to containing all apparatus mentioned as generally necessary for Higher Institutions in the "Normalverzeichnis fur die physikalischen Sammlungen der hoheren Lehr- anstalten", include, as well, all apparatus indicated as being desirable. Moreover, a series of appa- ratus has been considered which are now generally ordered at the same time. Collection 2 contains, under the objects designated by "1st Acquirement", all apparatus designated as necessary for "Higher Educational Institutions" and, in addition, an ample number of apparatus generally considered as desirable, and of new apparatus. The apparatus designated "2nd Acquirement" are in part designated as desirable and have, in part, been introduced during the last year or two. This Collection includes, like the previous one, an induction coil sufficient for produc- ing Bontgen Bays, for Tesla high frequency experiments, etc. Collection 3 comprises under the apparatus designated as "1st Acquirement" only those articles which are indicated as generally necessary for Higher Educational Institutions. For the "2nd Acquire- ment", which reaches nearly as high a sum as the "1st Acquirement", a number of the apparatus considered as desirable and a few more recent apparatus have been included. Collection 4 is intended for the minor institutions (such as the "Progymnaskn" in Germany). It comprises for the "I8t Acquirement" all apparatus designated as generally necessary for these institutions; and for the "2nd Acquirement" all those generally designated as desirable. By restricting the selection of the latter, the total sum can be diminished. This Collection is also well adapted for Continuation Schools, etc. 1076 Estimates of Cost for Physical Apparatus. Object It. ii German : Standard Collection Colle : 1st Ac- quirement ction 1 2nd Ac- quirement Colle 4 is' Ac- quirement ction 2 2nd Ac- quirement Collection 3 lat Ac- 2"d Ac- quirement quirement Colle 4 1st Ac- quirement 3tion I 2nd Ac- quin Apparatus, Supplies and Materials for General Use. 51,10i. 2 Universal stands (Bun- sen's) with single parts . 51,124. Gauss Stand, heavy construction 10 9 9 11 11 11 101 101 101 8 8 12 13 8 18 8 8 8 8 146 17 7 7 7 8 7 7 7 7 145 145 139 16& 19 141 140 19 £ s. d. 2. 4. 0 2. 0. 0 1. 1. 0 0. 10. 0 0. 4. 0 0. 0. 8 0. 0. 8 0. 4. 0 0. 16. 10 0. 5. 0 0. 2. 6 0. 3. 5 0. 1. 0 1. 4. 0 0. 15. 0 0. 3. 5 0. 8. 7 0. 2. 6 0. 9. 7 0. 2. 7 0. I.' 7 0. 0. 11 1. 0. 0 0. 1. 8 0. 1. 0 0. 2. 0 0. 1. 0 £ s. d. 0. 17. 0 0. 6. 0 0. 7. 0 0. 1. 4 £ s. d. 2. 4. 0 2. 0. 0 1. 1. 0 0. 10. 0 0. 4. 0 0. 0. 8 0. 17. 0 0. 0. 8 0. 16. 10 0. 5. 0 0. 2. 6 0. 3. 5 0. 1. 0 1. 4. 0 0. 15. 0 0. 3. 5 0. 8. 7 0. 2. 6 0. 9. 7 0. 2. 7 0. 1. 7 0. 0. 11 1. 0. 0 0. 1. 8 0. 1. 0 0. 2. 0 0. 1. 0 £ s. d. 0. 6. 0 0. 7. 0 0. 1. 4 £ s. d 2. 4. 0 2. 0. 0 1. 1. 0 0. 10. 0 0. 4. 0 0. 0. 8 0. 0. 8 0. 16. 10 0. 5. 0 0. 2. 6 0. 3. 5 0. 1. 0 1. 4. 0 0. 15. 0 0. 3. 5 0. 8. 7 0. 2. 6 0. 9. 7 0. 2. 7 0. 1. 7 0. 0. 11 1. 0. 0 0. 1. 8 0. 1. 0 0. 2. 0 0. 1. 0 £ s. d. •0. 17. 0 0. 6. 0 £ s. d. •2. 4. ii 2. ii. ii 1. 1. i» 0. 0. 8 0. 0. 8 0. Hi. 10 0. 5. 0 0. 2. 6 0. 3. 5 0. 1. 0 1. 4. 0 0. 15. I) 0. 3. 5 0. 8. 7 0. 2. 6 0. 6. 0 0. 9. 7 0. 2. 7 0. 1. 7 0. 0. 11 1. 0. 0 0. 1. 8 0. 1. 0 £ s. d. 0. 17. 0 0. 4. 0 0. 7. 0 0. 1. 4 51,132—51,134. 3 Tables for setting up apparatus . . 51,144. Levelling board . . . 51,147. Wood supports . . . 51,149. 1 Set of thin wood wedges .... 51,158. 1 Set flexible leads . . 5 1 , 1 60. Copper wire, double silk covered, 10 metres . . . 51,162. 0,5 kg of various copper wire, bare and insulated . 51,163. Kubber tubing of black rubber, No. 2/0, 1/0, 2, 3, 4, 6, 8; 2 metres each . 51,165. Rubber tubing, grey, for connecting up gas burners, 5 metres .... 51,184. 2 Bunsen burners, with- out tap . . each £ 0.1.3 51,208—51,211. 4 Spirit lamps 51,226. 3 Wire nets of iron . 51,292. 3 kg Mercury .... 51,320. Mortar, cast iron, with pestle 51,322. 3 Pulverising dishes . 51,336. 16 Rubber stoppers of different sizes 51,337. 100 Corks of various sizes Glass vessel 51,341. Measuring cylinders, 25, 50, 200, 500 and 1000 com capacity 51,345. Beakers, 10 in set . . 51,346. Test glasses, set of 30 in 3 sizes .... • . 51,352. 3 Porcelain dishes with tap, 60, 85 and 125 mm . Platinum wire, 30 cm of 0,35 mm Platinum Wire, 30 cm of 0,25 mm . . — Platinum sheet, 40 x 40 mm, 0,03 mm thick . . . 51,376. Boiling flasks, set of 7 51,389. Funnels, set of 4 . . 51,406. Bent tubing, 1 kg . . 51,410. 4 Stirring rods .... 51,414. Burettes, with glass stopcock, 25 and 75 ccm . 51,415. 2 floaters for above . Measuring of Length, Weight and Time. Introduction to Physics. 51,426. Linear vernier model . 51,433. Metre rule with co- loured graduation .... 51,459. Micrometer gauge . . 51,466. CathetoMieler .... 51,506. Litre vessel, cube shape Carried forward 12. 6. 11 0. 2. 0 0. 5. 0 1. 11. 4 0. 10. 0 0. 5. 6 7. 0. 0 12. 19. 11 0. 2. 0 0. 5. 6 (1. 5. II 0. 14. 4 0. 10. d 12. 2. 11 0. 2. 0 0. 5. 0 1. 3. 0 0. 10. 0 0. 5. 6 11. 11. 11 0. 2. 0 0. 5. 0 1. 9. 4 II. 1(1. ii 0. 5. 6 7. I'. i> 0. 7. 0| 7. 15. 6 0. 12. 6 0. 10. 0 l 0. 3. o 1. 12. 0 1. 4. ii <;. o. 6 0. 0. 6 0. 12. 0 0. 12. 0 1. 2. 0 1. 3. 0 0. 10. 0 0. 1C. ii 0. •> ii 1. 13. 6 0. 3. 0 1. 19. 0 1. 4. 0 0. 0. 6 0. 0. 6 ii I'-'. H II 12. ii 1. -2. 0 12. 18. 0 1. 1. 0 0. 10. 0 0. 16. 0 0. 18. 0 0. 2. (i 52,749. Barometer tube with mercury cup .... 52,758. Barometer tube with iron tube vessel 62,778. Syphon barometer . . 62,804. Aneroid barometer . . 62,818. Boyle's (Marietta's) law appara tus 52,828 Mairic jug 52,835. Mariotte's bottle . . . 52,838. Syphon, of glass . . . 52,840. Plunging syphon . . . 62,855. Heron's ball with rub- ber bellows 52,859. Heron's fountain . . . 52,861. Intermittent fountain 52,864. Cartesian diver . . . 52,870. Model of amiction pump 52,876. Model of a force pump 52,881. Model of a fire engine t'airieil forward (i. 10. ll 3. 11. 0 r>. 16. o o. -2. 6 .-). 6. 0 1. 8. 6 .-,. ii. ir :i. 7. •> 0. 4. 0 0. 4. I) 0. 4. u — 52,037. 1 >isc apparatus for alter- nating mixed colours . . 209 0. 8. 0 — 11. S. II — — — 54,355. Camera obscura . . . 59 1. 0. 0 — 1. 0. II 1. 0. U 1.0. 0 54,375. 3 Ligroin lamps . . . 51 0. 6. 0 — 0. (S. 0 (I. li. II — 54,408. Simple microscope . . 60 3. 5. 0 — :?. r». (i — 3. .->. li — :t. 5. o Carried forward 47. 4. 6 -2f. 1. (1 36. 4. 6 -24. 17. 0 14. 9. II 15. (i. II 12. 19. u li. 9. 0 Estimates of Cost for Physical Apparatus. 1081 Object Ho. In German Standard Collection Colle ] 1st Ac- quirement ction 1 ond Ac- quirement Collection 2 1st AC- 2nd Ac- quirement quirement Collection 3 1st AC- 2nd Ac- quirement quirement Collection 4 1st Ac- 2nd Ac- quirement quirement Brought forward 54,510. Newton's colour glasses, 100 mm diam., on stand. 54,520. Fresnel's mirrors . . . 54,599. Demonstration polari- sation apparatus after Grimsehl 197 198 194 196 193 193 195 £ s. d. 47. 4. 6 1. 10. 0 2. 12. 0 0. 16. 0 0. 15. 0 0. 10. 0 £ s. d. 23. 1. 0 1. 18. 0 1. 4. 0 £ s. d. 36. 4. 6 0. 16. 0 £ s. d. 24. 17. 0 1. 18. 0 0. 10. 0 £ s. d. £ s. d. 14. 9. 015. 6. 0 1. 18.' 0 0. 16. 0 £ s. d. 12. 19. 0 £ s. d. 6. 9. 0 54,624. Tourmaline tongs with 6 preparations 54,693. Glass plate with letters and calc-spar plate . . . 54,775. Calc-spar cube .... 54,735. Nicol prism, 10 mm side Heat and Meteorology. 54,785. Brass sphere with ring, after S'Gravesande . . . 54,797. Contraction apparatus (Tyndall's) with burner. . 54,799. Pyrometer for linear expansion 71 72 214 213 69 69 222 70 211 218 212 212 212 212 212 212 212 212 212 212 225 225 225 77 53. 7. 6 0. 5. 0 1. "0. 0 1. 8. 0 1. 4. 0 0. 1. 0 0. 3. 0 0. 6. 0 0. 2. 0 2. 10. 0 0. 4. 6 0. 8. 0 0. 12. 0 0. 12. 0 1. 12. 0 0. 4. 0 0. 10. 0 0. 16. 0 0. 16. 0 0. 12. 0 0. 1. 8 0. 8. 4 0. 5. 0 1. 4. 0 0. 2. 0 26. 3. 0 0. 18. 0 0. 18. 0 0. 5. 0 1. 16. 0 0. 4. 0 37. 0. 6 0. 5. 0 1. 0. 0 1. 8. 0 0. 1. 0 0. 3. 0 0. 6. 0 2. 10. 0 0. 4. 6 0. 12. 0 1. 12. 0 0. 16. 0 0. 1. 8 0. 8. 4 0. 5. 0 1. 4. 0 0. 2. 0 0. 4. 0 27. 5. 0 1. 4. 0 0. 5. 0 0. 2. 0 0. 8. 0 0. 12. 0 0. 4. 0 0. 10. 0 0. 16. 0 0. 12. 0 14. 9. 0 18. 0. 0 0. 5. 0 1. 0. 0 1. 8. 0 0. 18. 0 0. 1. II 0. 3. Ol 0. 5. 0 0. 6. 0 — 0. 2. 0 2. 10. 0 0. 4. 6 1 : 0. 12. 0 1. 12. 0 0. 10. 0 0. 16. 0 u. 1. 8 o. 8. 4 0. 5. 0 1. 4. 0 0. 2. 0 — , 0. 4. 0 12. 19. 0 0. 5. 0 1. 8. 0 0. 1. 0 0. 3. 0 0. 6. 0 6. 9. 0 0. 18. 0 0. 18. 0 0. 2. 0 2. 10. 0 0. 4. 6 0. 8. 0 0. 12. 0 1. 12. 0 0. 4. 0 0. 16. 0 54,822. Water dilatometer . . 54,823. Glass cylinder with heating device 54,835. Expansion of mercury 54,858. Simple thermometer . 54,859. Cylindrical thermo- meter from — 20° to +360° 54,862. Thermometer for calori- metric work 54,878. Thermometrograph after Six 54,891. Strips of steel and zinc 54,894. Metallic thermometer 54,955. Double thermoscope after Looser 54,956. Introduction to above 54,957a. Small collection of accessories for experiments on thermal expansion . . 54,958. Accessories for experi- ments on specific heats . 54 959a. Small collection of ac- cessories for experiments on thermal conduction . . . 54,962a. - - idem, for experi- ments on radiant 1-eat . . 54,963a. - - idem, for experi- ments on heat and work. 54,965a. - - idem, for experi- ments on change of state 54,966. — idem, for heat experi- ments on gases and vapours 54,968a. - - idem, for experi- ments on thermal effect of currents 54,969a. — idem, for using the thermoscope as a mano- meter 55,016. Hollow iron sphere with closing screw 55,017. 10 Spare iron spheres. 55,018. Cooling vessel for above 55,031. Steam barometer for showing the tension of water vapour 55,033. Copper dish for Leiden- frost's experiment .... 55,060. Water hammer . . . Carried forward 15. 6. 6 4. 1. 0 11. 2. 6! 4. 13. 0 3. 7. OJ 9. 10. 6 2. 3. 0: 8. 4. 6 1082 Estimates of Cost for Physical Apparatus. Object In. In German Standard Collection Collection 1 !»' Ac- 2"i Ac- quirement quirement Colle I 1st Ac- quirement ction 5 2nd Ac- quirement Colle £ 1st Ac- quirement ,'tion t 2nd Ac- quirement Collection 4 !»' Ac- ; 2nd Ac- quirement quirement Brought forward 55,070. Papin's digester with spring manometer .... 55,092 Steel cylinder for car- bonic acid 220 224 216 221 215 217 76 78 73 226 219 74 75 223 79 227 80 81 82 82 230 229 229 231 83 228 84 229 233 232 85 86 and 246 si; £ s. d. 15. 6. 6 2. 8. 0 1. 2. 0 0. 5. 0 0. 16. 0 5. 5. 0 3. 4. 0 1. 0. 0 4. 16. 0 0. 18. 0 0. 15. 0 1. 0. 0 1. 8. 0 £ s. d. 4. 1. 0 1. 10. 0 0. 5. 0 0. 6. 0 0. 8. 0 0. 6 0 0. 15. 0 1. 4. 0 0. 8. 0 1. 8. 0 £ s. d. 11. 2. 6 0. 6. 0 1. 2. 0 0. 5. 0 0. 16. 0 3. 4. 0 1. 0. 0 0. 8. 0 0. 18. 0 0. 15. 0 1. 0. 0 1. 8. 0 £ s. d. 4. 13. 0 2. 8. 0 0. 5. 0 0. 6. 0 0. 8. 0 1. 4. 0 5. 5. 0 4. 16. C £ s. d. 3. 7. 0 0. 16. 0 3. 4. 0 1. 0. 0 0. 18. 0 0. 15. 0 1. 8. 0 £ s. d. 9. 10. 6 2. 8. 0 0. 5. 0 1. 0. 0 £ s. d. 2. 3. 0 3. 4. 0 1. 8. 0 £ s. d. 8. 4. 6 It is presumed that the liquid air which is ne- cessary for the following experiences is obtained ready for use from the sup- pliers; if desired we supply apparatus for generating liquid air 55,116 Double walled capsule for obtaining solid air . . 55,117. Lead plate with ham- mer and dish 55,118. 2 small glasses with ether and alcohol .... 55,123. Apparatus for the criti- cal temperature phenomena 55,150. Specific heat of metal spheres 55,154. Ice calorimeter .... 55,169. Water calorimeter . . 52,048. Friction heat .... 55,223. Pneumatic fire syringe 52,050. Puluj's apparatus . . 55,265. Sectional model of a steam engine 55,289. Thermal conduction in metal rods (Ingenhouss) . 55,306. Davy's safety lamp . 55,330. 2 spherical concave mirrors, 300 mm diam. . 55,358. Leslie's cube 55,443. Hygrometer afterDaniel 55,453. Polymeter.Lambrecht's 55,458. Psychrometer, August's 55,487. 6 Meteorological maps Magnetism. 60,002. Lodestone . . 38. 3. 6 0. 12. 0 1. 4. 0 0. 3. 0 0. 2. 6 0. 1. 6 0. 1. 9 0. 1. 6 2. 8. 0 0. 1. 0 0. 3. 0 10. 11. 0 0. 15. 0 0. 5. 0 1. 10. 0 3. 15. 0 2. 0. 0 22. 4. 6 0. 12. 0 1. 4. 0 0. 3. 0 0. 2. 6 0. 1. 6 0. 1. 9 0. 1. 6 0. 1. 0 19. 5. 0 0. 5. 0 2. 8. 0 0. 3. 0 2. 0. 0 11. 8. 0 0. 12. 0 1. 4. 0 0. 3. 0 0. 2. 6 2. 8. 0 0. 1. 0 13. 3. 6 0. 1. 6 0. 1. 9 0. 1. 6 0. 5. 0 0. 3. 0 2. 0. 0 6. 15. 0 0. 12. 0 1. 4. (• 0. 3. 0 0. 2. 6 2. 8. 0 0. 1. 0 8. 4. 6 0. 15. 0 1. 10. 0 60,005. 2 Bar magnets and 2 horse shoe magnets . . 60,026. Horse shoe magnet with 5 segments 60,046. Magnetic needle, 100mm 60,058. Stand for same . . . 60,080. Glass tube, half filled with iron filings 60,082. Iron powder, 250 g. . 60,083. Sifter for above . . . 60,084. Soft iron rod .... 60,098. Dip circle 60,119. Ship's compass .... — Knitting needles for magnetizing 62,363. Wood frame, with card- board 60,129. Magnetometer .Weber's 60 131. Decrease of magnetic force with distance . . . Static Electricity. 60,142. Different rods with rubbers 4. 18. 3 1. 0. 0 1. 4. 0 0. 5. 0 8. 5. 0 2. 7. 3 1. 0. 0 1. 4. 0 0. 5. 0 4. 16. 0 4. 10. (i 1. 0. 0 1. 4. 0 0. 5. 0 2. 12. 9 4. 10. <> 2. .V ii i. o. o 0. 5. 0 — 60,158. Electric horizontal pendulum 60,160. Double electric pen- dulum Carried forward 2. 9. 0 2. 9. 0 2. 9. 0 — 1. 5. 0 Estimates of Cost for Physical Apparatus. 1083 Object No. In German Standard Collection Colle 1st Ac- quirement ction t 2nd Ac- quirement Colle i 1st Ac- quirement ction J 2nd Ac- quirement Colle • 1st Ac- quirement ction I 2nd Ac- quirement Colle . < is' Ac- quirement ction I 2nd Ac- quirement Brought forward 60,186. 2 Electroscopes (von Beetz's), each £ 1 . 2. 0 . . 60,190. Electrometer (Szy- mauski's) 87 238 240 234 243 244 246 243 243 243 243 243 243 243 243 243 243 92 88 93and 235 88 90 89 89 89 89 241 242 95 94 236 96 91 237 239 246 97 100 98 100 100 99 £ s. d. 2. 9. 0 2. 4. 0 1. 0. 0 0. 18. 0 3. 10. 0 2. 15. 0 0. 12 0 0. 12. 0 3. 10. 0 4. 10. 0 0. 1. 0 0. 7. 0 0. 9. 0 0. 4. 0 0. 4. 0 0. 1C. 0 " 1. 4. 0 0. 14. 0 1. 10. 0 0. 4. 0 £ s. d. 2. 10. 0 3. 0. 0 3. 0. 0 1. 13. 0 0. 5. 0 2. 5. 0 0. 12. 0 0. 12. 0 0. 4. 6 0. 10. 0 0. 12. 0 4. 10. 0 1. 7. 0 2. 0. 0 2. 8. 0 1. 0. 0 1. 0. 0 £ s. d. 2. 9. 0 2. 4. 0 3. 0. 0 3. 10. 0 2. 15. 0 0. 12. 0 0. 12. 0 3. 10. 0 4. 10 0 0. 1. 0 0. 7. 0 0. 9. 0 0. 4. 0 0. 4. 0 0. 10. 0 1. 4. 0 0. 14. 0 1. 10. 0 0. 4. 0 £ s. d. 3. 0. 0 1. 13. 0 0. 5. 0 2. 5. 0 0. 12. 0 0. 12. 0 0. 4. 6 0. 10. 0 0. 12. 0 4. 10. 0 £ s. d. 2. 9. 0 2. 4. 0 0. 12. 0 3. 10. 0 4. 10. 0 0. 1. 0 0. 7. 0 0. 9. 0 0. 4. 0 0. 4. 0 0. 10. 0 1. 4. 0 0. 14. 0 1. 10. 0 0. 4. 0 £ s. d. 1. 0. 0 3. 0. 0 3. 10. 0 2. 15. 0 3. 0. 0 1. 13. 0 0. 5. 0 2. 5. 0 0. 12 0 0. 12. 0 0. 4. 6 0. 10. 0 0. 12. 0 4. 10. 0 0. 12. 0 £ s. d. 1. 5. 0 2. 4. 0 0. 12. 0 3. 10. 0 4. 10. 0 0. 1. 0 0. 7. 0 0. 9. 0 0. 4. 0 0. 10. 0 1. 4. 0 0. 14. 0 0. 4. 0 £ s. d. 1. 0. 0 0. 18. 0 • 1. 0. 0 60,230. Distributing apparatus 60,244. Electricity resides on the surface tiit. l!H5. Aluminium Electro- meter (Kolbe's) (in. m. Odstrcil's apparatus for demonstrating Coulomb's law 60,257. Electrometer (Bohnen- berger's) Apparatus for the study of potential see the follow- ing apparatus Nos. 60,258, 60,260 to 60,279. 60,258. Water battery .... 60,260. 2 Small electroscopes . 60 261. Sheet iron Cube . . . 60,262. 2 Hollow cylinders . . 60,263. Hollow cylinder . . . 60,264. Insulating table . . . 60,265. Paraffin plate .... 60,266. 2 fixed sounders with solid balls and hollow halls 60,267. Adjustable sounder . . 60,268 — 60,279. Accessories . . 60,300. Flexible wire netting . 60,358. Electrophorus of 21 cm diameter 60,370. Disc electric machine, 36 cm diameter of disc . 60,436. Self exciting influence machine 60,521. Connecting chain, 1 m 60,526. Insulating stool . . . 60,528. Chime .... 60,532. Electric whir! . . . 60,535. Paper tassel 60,536. Electric dancing balls 60,577. Electric egg . 60,569. Electric air thermometer 60,581. 2 Leyden jars, 40 cm high, each £ 0. 12. 0 . . . 60,584. Leyden jar with re- movable coating .... 60,586. Leyden jar battery, 4 jars of 26 cm height . 60,608. Condenser (Weinhold's) 60,621. Discharger . . 60,625. Henley's discharger . . 60,605. Lane's measuring jar . Voltaic Electricity. Bohnenberger's electro- scope see Static electricity 60,684. Volta's pair of plates . 60,737. Zinc-copper cell with separate carbon electrode. 60,762. Daniell's cell 27. 7. 0 0. 16. 0 0. 3. 0 0. 5. 0 0. 10. 6 0. 2. 6 o. 2. 0 :;. i-j. it 27. 8. 6 28. 9. 0 0. 3. 0 0. 5. 0 0. 10. 6 0. 2. 6 o. -2. 0 3. 12. 0 14. 3. 6 18. 12. 0 0. 3. 0 0. 5. 0 0. 10. 6 0. 2. 6 0. 2. 0 3. 12. 0 25. 0. 6 15. 14. 0 0. 3. 0 0. 5. 0 0. 10. 6 0. 2. 6 0. 2. 0 3. 12. 0 2. 18. 0 60 781. 3 Bottle cells (Grenet's), each £ 0. 3. 6 . . 60,785. Leclanche cell .... 60,792. 2 HelU-sim dry cells, each £ 0. 1. 0 . . 60,821. Immersion battery with 6 cells Carried forward 5. 11. 0 4. 15. 0 4. 15. 0 4. 15. 0 — 1084 Estimates of Cost for Physical Apparatus. Object No. il German Standard Collection Collection 1 1st AC- 2nd Ac- quirement quirernent Colle S 1st Ac- quirement etion 5 2nd Ac- quirement Colle J 1st Ac- quirement ction t 2nd Ac- quirement Collei 4 1st Ac- quirement :tion I 2nd .\c- quiremeul Brought forward 61,093. 4 Terminals, each £0.0. 4 61,134. Commutator (Ruhin- korffs) . . 101 103 102 105 104 258 247 248 115 261 262 249 250 106 251 260 107 254 111 257 265 259 253 108 108 252 1091) 109 110 266 267 267 867 268 £ s. d. 5. 11. 0 0. 1. 4 0. 16. 0 0. 10. 0 7. 0. 0 3. 15. 0 3. 0. 0 0. 3. 0 3. 0. 0 3. 10. 0 1. 12. 0 1. 0. 0 0. 2. 0 £ s. d. 2. 10. 0 2. 10. 0 1. 16. 0 1. 4. 0 £ s. d. 4. IS. 0 (t. 1. 4 (1. 16. 0 0. 10. 0 7. 0. 0 3. 15. (I 2. 10. 0 2. 10. 0 0. 3. 0 1. 4. 0 3. 10. 0 1. 12. 0 1. 0. 0 0. 2. 0 £ s. d. 3. 0. 0 1. 16. 0 £ s. •!. 4. 15. 0 0. 1. 4 0. 16. 0 0. 10. 0 7. 0. 0 3. 15. 0 0. 3. 0 1. 12. o £ s. d. 2. 10. 0 •2. Id. o 1. 4. 0 3. 1C. n 1. d. n (I. -2. 0 £ s. d. 4. 15. 0 0. 1. 4 0. 16. 0 o. 10. 0 3. 15. 0 0. 3. 0 1. 12. 0 t s. d. 1. 0. n 0. 2. 0 61 147 Morse key 61,268. Tangent galvanometer 61,299. School galvanometer (astatic) 61,397. Moving coil mirror gal- 61,520. Demonstration ammeter 61,521. Demonstration volt- 61,854. Resistance of 1 ohm . 61,882. Switch contact rheostat 62,117. Foster's apparatus . . 61,903. Simple Wheatstone bridge .... 62,006. Rheostat with 8 pings 62,193. Voltameter, Hofmann's 62,256. Electro -plating appa- ratus for copper deposits 62,254. 2 Matrices of gutta- percha, each t' 0. 1. 0 . . Electro-magnetism, High frequency, Electric waves and Thermo-Electricity. 62,261. Oersted's apparatus . . 62,280. Electromagnet after Weinhold .... 30. 0. 4 2. 4. 0 2. 4. 0 0. 8. 0 4. 4. 0 0. 8. 0 0. 4. 0 0. 16. 0 1 4. 0 0. 16. 0 0. 2. 0 0. 16. 0 17. 10. 0 1. 0. 0 0. 10. 0 1. 0. 0 (». 5. 0 1. 10. 0 2. 15. 0 1. 0. 0 1. 0. 0 1. 5 0 7. 5. 0 8. 0. 0 0. 18. 0 1. 10. 0 3. 10. 0 1. 8. 0 4. 1. n 29. 8. 4 2. 4. 0 0. 8. 0 4. 4. 0 0. 8. 0 0. 4. 0 0. 16. 0 0. 2. 0 17. 10. 0 1. 0. II o. 10. o 1. 0. 0 0. 5. u 1. 10 0 •>. I.',, n 7. .">. 0 4. 16. 0 2 4. 0 3. 10. 0 1. 0. 0 1. .->. n 18. 12. 4 2. 4. 0 0. 8. 0 0. 16. 0 0. 2. 0 2. 15. 0 •2. 15. 0 10. 16. 0 0. 18. 0 1. 10. 0 2. 4. 0 4. 4. t! 0. 8. 0 0. 4. 0 0. 16. 0 1. 4. 0 1. _8. 0 0. 16. 0 ]. n. n 1. :>. n 11. 12. 4 2. 4. 0 II. 8. 0 0. 16. 0 0. 2. 0 •2. 15. 0 1. 2. 0 2. 4. 0 0. 16. (1 62,280a. v. Waltenhofen's pen- dulum 62,325. Morse telegraph . . . 62 351 Electric bell 62,383. Ampere's stand . . . 62,367. Wire coil for above . 62 368 Zinc plate 62,371. Explaining the theory of lines of magnetic force 62,408. Roget's spiral .... 62,414. Rotation of a magnet about a current 52,061. Apparatus for gene- rating Foucault currents . 62,444. 2 Induction coils after 60,007. Cylindrical bar magnet for above 62,464. Magnetic hammer break 62,637. Induction coil for 200 mm spark-length . . 62,660. Induction coil for 30mm spark-length . . 62,589. Sparking pillars . . . 62,652. Small induct ion coil, 6 mm spark-length . . . 62 690 X-ray tube 51,110. Simple wood stand . . 62,707. Fluorescent screen size 13 x 18 cm 62,735. Model of a I'acinotti- Gjamme-maohine .... 62,737. Model of a magneto- li-J.7.">s. Schuckcrt flat ring . . 62,759. Siemens armature . . 62,762a. Drum armature . . . 62,781. Shunt dynamo for gene- rat inir eurrenl Carried forward 48. <>. 0 11. 10. 0 40. 1. 0 7. 19. 0 < \nerimei !>. II. 0 15. 17. (I Is with X-rays. li. '). 0 3. n. n ') This induction coil is sufficiently large to permit of making Estimates of Cost for Physical Apparatus. 1085 Object Do. in German Standard Collection Colle ] 1st Ac- quirement ction I 2nd Ac- quirement Collection 2 let Ac- 2nd Ac- quirement quirement Colle J 1st Ac- quirement ction t 2nd Ac- quirement Colle! < 1st Ac- quirement jtion I 2nd Ac- quirement Brought forward 62,797. Glow lamp stand with glow lamp 112 113 264 264 255 256 114 263 £ s. d. 48. 6. 0 0. 6. 0 2. 0. 0 0. 8. 0 0. 15. 0 0. 11. 0 • 4. 0. 0 10. 0. 0 2. 2. 0 0. 6. 0 0. 8. 0 1. 2. 0 £ s. d. 11. 10. 0 6. 0. 0 6. 10. 0 £ s. d. 40. 1. 0 0. 6. 0 2. 0. 0 0. 8. 0 6. 10. 0 4. 0. 0 10. 0. 0 2. 2. 0 0. 6. 0 0. 8. 0 £ s. d. 7. 19. 0 — £ s. d. 9. 0. 0 0. 6. 0 •2. 0. 0 0. 8. 0 £ s. d. 15. 17. 0 0. 8. 0 0. 15. 0 C. 11. 0 6. 10. 0 4. 0. 0 10. 0. 0 2. 2. 0 0. 6. 0 1. 2. 0 £ s. d. 6. 5. 0 0. 6. 0 2. 0. 0 £ s. d. 3. 0. 0 2. 2. 0 62,903. Demonstration appara- tus for rotating field ex- periments ... . . . 62,81.5. Small arc lamp . . . 63,022. 6 Geissler tubes . . . 63,053. Hittorffs tube .... 63,096. Crookes' tube No. 15 . 63,241. Set of Tesla apparatus 63,268. Apparatus for repeating Hertz's experiments . . . 63,310. Wireless telegraphy de- monstration apparatus . . 63,360. Explaining the working of the telephone .... 63,374. Model of a microphone 63,413. Rod shaped thermo- couple 63,426. Thermopile Total cost of Collections 1—4. Apparatus, etc. for general use Measuring of length, weight and time ; Introduction to physics 70. 4. 0 24. 0. 0 is' and 2nd Acquirement 13. 18. 3 22. 5. 0 5. 9. 0 29. 16. 6 22. 2. 6 21. 5.9 40. 1. 0 79. 10. 6 48. 14. 6 13. 3. 3 54. 15. 6 38. 0. 4 94. 4. 0 06. 1. 0 7. 19. 0 1st and 2nd Acquirement 13. 14. 3 13. 0. 0 4. 12. 0 17. 16. 6 14. 4. 6 16. 11. 3 28. 8. 0 64. 5. 6 41. 9. 6 7. 3. 3 42. 12. 6 34. 4. 4 74. 0. 0 11. 14. 0 41. 11. 0 1st and 2nd • Acquirement 13. 5. 11 3. 12. 0 4. 12. 0 14. 9. 9 . 4. 4. 6 17. 7. 3 21. 18. 0 32. 9. 0 24. 11. 6 7. 3. 3 43. 12. 6 29. 8. 4 53. 5. 0 8. 11. 0 5. 2. 0 1st and 2nd Acquirement 13. 1.3 21. 16. 0 1. 12. 0 12. 19. 0 14. 11. 6 19. 6. 3 13. 8. 0 19. 8. 0 14. 19. 6 6. 15. 6 18. 12 0 12. 14. 4 13. 13. 0 General mechanics Mechanics of solids .... Mechanics of liquids Mechanics of gases .... Wave motions and acoustics . Optics Heat and Meteorology .... Magnetism . . Static electricity . . Voltaic electricity Electromagnetism - - Thermo- electricity The total cost is distributed on the 1st and 2nd acquirement to . 483. 311. 5. 9 6. 1 172. 0. 4 372. 270. 1. 3 1. 7 102. 0. 4 269. 19. 0 147. 6. 3 122. 12.9 182. 111. 12.6 Hi. 4 71. 3. 10 Estimates of Cost for Chemical Supplies. In compiling this Collection it is assumed that physical instruction is imparted in a different room from chemical instruction. If, however, the classroom is common to both branches, the objects listed in the section "Apparatus, Supplies and Materials for General Use" can be entirely or partly dispensed with if already available in the Physical Collection. It is further assumed that the "Equipments", and especially Lecture Table with gas, water and electric leads, etc., Cupboards, Eeagent Stands, Tools and perhaps also an experimental Switch- board, or an electric Transformer, Water Air Pump, Water Jet Blower, etc. necessary for the Chemical Classroom, the Preparation Eoom and the Laboratory, are either available or will be ordered separately. 1086 Estimates of Cost for Chemical Supplies. Estimates as to Equipments: see Vol. I. The prices may be changed for platinum goods at the time of ordering in proportion to th< price prevailing for platinum. Collection 5. This Collection contains the articles designated as generally necessary and desirable in the "Standard Code" (further particulars on p. 1075). A Collection of Chemicals in small quantities, with bottles for same provided with inscription, also in small quantities, is appended. Apparatus, Supplies and Materials for General Use. These objects are selected conforming the collection No. 3 re Physical apparatus and can be dispensed with when a common class room is employed for physics and chemistry. Standard- £ s. d. Code — Apparatus, supplies and materials 1(1~, like p. 1076, collection No. 3, !»' I i^-i4i\13 5- n and 2»d acquirement 1 1 43-1 46 J 51,533. Analytical balance, also suitable for specific gravity determinations . 142 7. 15. 0 51,578. Outfit for specific gravity deter- minations 0. 9. 0 51,637. Rider weights 142 0. 5. 6 51,642. Precision weights, from 1 mg to 200 g 142 0. 15. 6 51,570a. Pillar tare balance 14 1. 8. 0 Short pan for above 14 0. 5. 0 51,657. Precision weights, from 100 mg to 1000 g 15 0. 16. 6 25. 0. 5 Special Supplies. 51,232. Water bath with insertion rings 116 0. 8. 0 51,256. Gasometer of glass 117 2. 0. 0 51.339. Pneumatic trough 118 1. 0. 0 51.340. 5 Glass receiving cylinders ... 119 0. 5. 1 51,378. 3 Measuring flasks, without stop- pers, 25, 100 and 500 com cap. . . 120 0. 1. 7 3 Measuring flasks, with stoppers, 50, 250 and 1000 com 120 0. 3. 0 51.341. 10 Measurings cylinders with lip 120 1. 1. 9 51.322. 3 Pulverising dishes 121 0. 3. 5 Platinum crucible with lid, 12 g weighing, 12 com capacity (Price is subject to fluctuation) 122 4. 5. 0 51,364-51,366. 6 Hessian crucibles in 3 sizes 123 0. 0. 8 51,309. Crucible tongs 124 0. 1. 0 51.323. Blow pipe collapsible 125 0. 2. 0 51,403. 2 Gas washing flasks 126 0.1. 10 51,395. Drying tube 126 0. 4. 0 51.382. 6 Retorts without tubes .... 127 0. 2. 3 51.383. 6 Retorts with tubulure and ground in stopper 127 0. 4. 3 51.386. 3 Receivers for retorts, without tube 127 0. 1. 1 51.387. 3 Receivers for retorts, with 1 tube 127 0. 1. 5 51.388. 3 Receivers for retorts, with 1 tube and ground-in stopper . . . 127 0. 1. 10 51,390. 4 Funnel tubes 128 0. 0. 11 51.346. 30 Test glasses in 3 sizes ... 129 0. 1. 7 51.347. Test glass stand 129 0. 1. 6 51.172. 2 Cocks of pressed glass .... 130 0. 2. 0 51.173. Three-way cock 130 0. 2. 0 51.174. Brass tap with 2 undulated hose pieces 130 0. 2. 6 51.401. 30 hardened filters in 3 sizes of 4, 11 and 24 cm diameter .... 131 0. 2. 3 51.402. 50 Sheets of filter paper, medium thick 131 0. 6. 6 54.858. 2 Simple cylindrical thermometer for 0° to 100° C 132 0. 2. 0 54.859. Cylindrical thermometer for — 20" to -+-3600 C 132 '). 3. o II. \-2. 5 Further Supplies und Apparatus. Standard- Code 50,961. Retort for generating oxygen . 269 51,282. Hydrogen generating apparatus (Kipp's) 270 Apparatus'for electrolysis and syn- thesis of water 271 51,282. Sulfuretted-hydrogen-generating Apparatus 272 51,407. 3 Spherical tubes 273 51,417. 3 Eudiometers 271 62,220. 3 U-shaped tubes with platinum and carbon electrodes 275 51.252. Gasometer, 30 1. capacity . . . 276 51.253. —idem, 50 1. capacity ... 276 Chemicals and Bottles for same. The inscription on the bottles contains both the chemical formula and the written out description given below. For a more complete collection with larger supply of chemicals, see p. 1090. Ill different solid and 39 different liquid chemicals £ s. d. 0. 12. 0 0. 10. 0 1. 4. 6 0. 10. 0. 2. 0. 12. 3. 10. 2 5. 3. 0. 12. 6. 2 s. d. 10. 0 S S s s S03 H3B03 H3B03 Na2B407 Na2B,07 C C Br KBr I KI HF1 SiO., P P As As2O3 Sb SbS H,(C4H.O.l K KCI KOH K..S KN03 KC10, 1. Solid Chemicals. Sulphur Flowers of Sulphur Sulphur Turnings Sulphur in rods Sulphur Trioxide (fused solid in glass tube) Boric Acid, artificial Boric Acid, natural Borax, artificial Borax, natural Graphite Carbon Bromine Potassium Bromide Iodine Tincture of Iodine Potassium Iodide Potassium Iodide Starch Paper Diamond Ink Kieeelgai Phosphorus, white Phosphorus, red Thomas Meal Guano. Arsenic White Arsenic Antimony Sulphide of Antimony Taitarised Antimony Starch Meal (lor Bengal Light*) Indigo Litmus Sugar Tartaric Arid Potassium Potassium Chlorate Caustic Pota-li Poiiissiiiiii Sulphide Potassium Nitrate Potassium Sulphate Potassium Carlmiinlc Kainite Estimates o! Cost for Chemical Supplies. 1087 Na NaCl NaCl NaOH Na2CO3 Na2S04 NaNO, NaNO. (NH4)(N03) NaHC03 (NH4)C1 CaS04 CaCO, CaC2 CaP BaCl2 Ba(OH)2 Sr(N03)2 Mg Mg Mg MgS04 Al Al Al Al A12(S04)3 ALK2(S04)4 Fe203 Fe FeS04 FeS K3Fe(CN)6 K4Fe(CN)6 MnO, KMn"04 ZnO ZnS04 CrO3 KXr04 K^O, Cr203 (II4N)2Cr20, Zn Mn Cr CoCl2 CuO CuS04 CuCL PbO Pb304 Pb(N03)2 (CH3COO)2Pb AgNO, Ag Sfo'' gf Bi Sn Sn SnCl, SnS, Pt " Au Sodium Sodium Chloride Cattle Salt Sodium Hydrate Sodium Carbonate Sodium Sulphate Sodium Sulphite Sodium Thiosulphate Sodium Nitrate Chili Saltpeter Ammonium Nitrate Sodium Bicarbonate Ammonium Chloride Powdered Plaster Chalk, powdered Calcium Carbide Calcium Phosphide, for mak- ing II3P Barium Chloride Barium Hydroxide Strontium Nitrate Magnesium Wire Magnesium Tape Magnesium Powder Epsom Salts Aluminium Bars Aluminium Wire Aluminium Powder Aluminium Foil Aluminium Sulphate Common Alum Ferric Oxide Iron Powder Ferrous Sulphate Iron Sulphide Potassium Ferricyanide Potassium Ferrocyanide Manganese Dioxide Potassium Permanganate (dark glass) Zinc Oxide Zinc Sulphate Chromium Trioxide Potassium Ctromate Potassium Bichromate Chromium Sesquioxide Ammonium Bichromate Zinc Manganese Chromium Cobalt Chloride Cupric Oxide Copper Sulphate (dark glass) Cupric Chloride Lead Oxide White Lead Lead Nitrate Lead Acetate Silvsr Nitrate (dark glass) Silver Sheet Mercury Chloride (dark glass) Mercury Oxide (dark glass) Mercury Cadmium Bismuth Tin Rods Tinfoil Stannic Chloride Stannic Sulphide Platinum Sheet Gold Sheet XaOII 10 Ml H3N HC1 HC1 HNO, 11X0.. HN03 H2S04 (CH3)(COOH) H,02 cs"2 C.,H6OH c;HnOH C,,H10N202 (C2HS)20 P in CS.. KJ K2S K2C03 Na2S04 Na2CO, Na2S03' KC10 CaCl2 Ca(OH)2 K.,Cr20, KMn04 Fe2(S04)3 FeCl3 ZnSO4 CuS04 CuCl2 HgCl, Pb(N03)2 PtCl4 2. Liquid Chemicals. Caustic Soda Caustic Potash Liquor Ammonii Muriatic Acid, crude Muriatic Acid, pure Nitric Acid, crude Nitric Acid, pure Nitric Acid, fuming Sulphuric Acid Acetic Acid, dilute Hydrogen Superoxide Carbon Bisulphide Alcohol, absol. Amyl Alcohol Indigo Solution Ether (dark glass) Phosphorus dissolved in Car- bon Bisulphide Tincture of Litmus Potassium Iodide Potassium Sulphide Potassium Carbonate Soluble Glass Glauber Salt Soda Sodium Sulphite Eau de Javelle Calcium Chloride Calcium Hydroxide Chloride of Lime Solution Potassium Bichromate Potassium Permanganate Ferric Sulphate Iron Chloride (dark glass) Zinc Sulphate Copper Sulphate (dark glass) Cupric Chloride Mercuric Chloride (dark glass) Lead Nitrate Platinum Chloride (dark glass) £ s. d. 51,370. 105 Bottles for reagents, of 100 ccm, with wide neck for solid chemicals with burnt-in black inscription and tall stoppers, of trans- parent glass, £ 0. 1. 1 each 5. 13. 9 51,370. 5 idem, of brown glass, £ 0. 1. 21/., each 0. 6. 0 51,370. 34 idem of 100 ccm with narrow neck for fluids, of transparent glass, £ 0. 1. 1 each . 1. 16. 10 51,370. 5 idem of brown glass, £ 0. 1. 21/., each 0. 6. 0 15. 12. Total Cost of Collection 5. Supplies for General Use 25. 0. 5 Special supplies 11. 12. 5 Further supplies and apparatus 12. 6. 2 Chemicals and bottles 15. 12. 7 64. 11. 7 If for instructions in chemistry and physics common rooms are employed, the sum diminishes for £ 25. 0. 5, so that the result is 39. 11. 2 1088 Estimates of Cost for Chemical Supplies. Collection 6. Chemical Supplies, Materials and Apparatus after the indications of Prof. Friedr. C. G. Miiller, Brandenburg. Supplies for pupils' exercises, assembled by Prof. Schaefer, Kecklinghausen. Stands, Small Tables, Supports. For Real- For anstalten Gymnasia Number £ 8. d. Number £ s. d. 51,104. Universal stand (Bunsen's) with ac- For Real- anstalten Number £ s. d. 2. 4. 0 2. 4. 0 51, 104'. Iron stands with- out accessories . . . 2 0. 3. 4 51, 104 a. Bunsen burners for above 2 0. 7. 0 1 0. 3. 6 51, 106. Heavy iron tripod 1 0. 3. 0 51, 111. Filter stand . . 1 0. 5. 6 — — 51, 132. Table for setting up apparatus, adjust- able from 25 — 30 cm 1 0. 6. 0 — — 51, 133. — idem, adjust- able from 25 — 40 cm 1 0. 7. 0 — — 61, 147. Wood supports . 4 sets 0. 16. 02 sets 0. 8. 0 51, 150. Wide woodwedges 2 sets 0. 2. 0 1 set 0. 1. 0 51, 220. Tripod of iron, 100 mm diam. . . . 1 0. 1. 0 — — 61, 222. — idem, 150 mm diam 1 0. 1. 4 61, 224. Wire triangles . 2 0. 0. 2 2 0. 0. 2 51, 226. Wire nets of iron 3 0. 1. 0 3 0. 1. 0 51, 227. — idem, of brass 3 0. 1. 3 3 0. 1. 3 51, 293. Mercury board, can be used as a tray 2 0. 14. 0 2 0. 14. 0 Adjustable tube stands 2 0. 6. 0 2 0. 6. 0 Total . £ 5. 18. 7 £ 3. IS. 11 Burners and Accessories. 51, 184. Bunsen burners . 3 0. 3. 9 2 0. 2. 6 51, 195. Universal gas burner (Teclu's) . . 1 0. 4. 6 a 0. 4. 6 51, 195. A-E. Attachments and chimney . . . 1 0. 8. 8 i 0. 8. 8 51,201. Gas burner with 4 burners arranged in a row 2 1. 14. 0 2 1. 14. 0 51,202. Gas burner (Dier- bach's) 1 0. 10. 0 Combustion fur- nace after v. Babo, with 20 burners . . 1 2. 10. 0 — Blast furnace (Flet- cher's) 1 1. 0. 0 Gas blast lamp with lever adjustment . . 1 0. 16. 0 1 0. 16. 0 Portable draught furnace for charcoal or coke 1 3. 15. 0 — — Total . £ 11. 1. 11 £ 3. 5. 8 Hollow ware of glass, porcelain, clay etc. 61 ,377. Boiling flask of glass of Jena 100 ccm .... 20 0. 6. 8 10 0. 3. 4 200 , 20 0. 8. 4 5 0. 2. 1 500 , 10 0. 6. 8 2 0. 1. 4 1000 „ .... 5 0. 5. 0 2 0. 2. 0 — Beakers of glass of Jena, with lip 50 ccm .... 4 0. 1. 0 2 0. 0. 6 150 „ .... 4 0. 1. 6 2 0. 0. 9 400 4 0. 2. 4 2 0. 1. 2 800 „ .... 4 0. 2. 10 2 0. 1. 5 1500 „ .... 4 0. 4. 0 2 0 2. 0 — Flasks, Erlenmi'vcr - form, of glass of Jena 100 ccm .... 10 0. 2. 6 2 0. 0. 6 300 „ .... 10 0. 4. 2 4 0. 1. 8 600 10 0. 6. 0 4 0. 2. 5 1100 „ .... 5 0. 4. 0 2 0. 1. 8 51 ,384. Retorts without tube, of glass of Jena, 100 ccm . 5 0. 1. 8 — 250 com .... 5 500 5 1000 „ . . . . 5 Retorts of refrac- tory potash -gl ;i >s. liV. ccm. ... 3 Retorts with tubu- lure and stopper, of glass of Jena 250 ccm .... 3 500 , 2 1000 , 1 51,386. Receivers for re- torts, without tube 250 ccm .... 3 500 „ .... 2 1000 „ 1 51.388. Receivers for re- torts, with tube and ground-in stopper 250 ccm .... 1 500 2 1000 ,,..'.. 1 51,346. Test glasses 100 mm .... 50 150 , 50 180 , 50 — Test glasses of re- fractory glass, 160 mm 10 51.389. Funnels of glass, different sizes, 5 to 15 cm 6 — Gas bottles with 2 tubes 4 51,,390. Funnel tubes(safe- ty tubes) 200 mm .... 5 400 „ . . . . 5 — Hot water funnel, 130 mm 1 — Safety funnels . . 300 "mm .... 1 400 , 2 500 „ . . . . 1 Woulff flasks with 3 necks, 500 ccm . 3 51.380. 1000 ccm .... 3 — Flask with 2 necks and tubulature on the side, near the bottom, 500 ccm 1 51.381. 1000 ccm .... 1 2000 „ . . . . 1 51,394. Drying cylinder, 250 mm high ... 1 400 mm high . . 1 51,368b. Powder jars with flat stoppers . . . 150 ccm .... 10 200 10 300 10 500 , 10 1000 „ . . . . 5 — 2000 5 51,369b. Bottles for liquids, with flat stoppers 1.1(1 ccm .... 10 200 10 300 10 500 10 1000 5 2000 ..... 2 — 4000 .... 1 0. 0. 0. •2. 4. 5. For Gymnasia Number £ s. d. 2 0. 1. 0 0. 3. 0 — 0. 0. 0. 0. 0. 0. 0. 0. 0. 3. 3. 2. 0. 1. 1. 2. 2. 3. 7 — 8 — 1 10 1. 0 — 0. 1. 0. 0. 0. 4. 0 — 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 3. 4. 0. 1. 0 0. 1. 7 0. 4. 0 0. 4. 7 0. 6. 0 0. 8. 0 0. 6. 0 0. 9. 6 0. 3. 0 0. 3. 6 0. 4. 6 0. 6. 4 0. 4. 9 0. 3. 0 0. 2. 7 0. 0. 8 0. 0. 6 0. 1. 0 0. 4. 3 — 0. 1. 3 0. 2. 4 0. 4. 0 51,406. Bent tubing 2 kg 0. 4. 0 — Estimates of Cost for Chemical Supplies. 1089 For For Realanstalten Gymnasia Number £ s. d. Number £ s. .51, 351. Crystallising dishes 10 0. 6. 0 — Flasks with side neck, 500 com ... 2 0. 2. 0 — 1000 ccm . . . . 2 0. 2. 11 — Combustion tubes, 350 mm long, 20 mm wide 20 0. 8. 0 10 0. 4. - idem, shut at one end 10 0. 5. 0 5 0. 2. .">l.:(tu. Hessian crucibles, 8 cm high 3 0. 0. 3 — Graphite crucible, 95 x55 mm .... 2 0. 1. 0 51.413. Burettes with pinch cock, 50 ccm. 1 0. 2. 6 — 100 ccm .... 1 0. 4. 6 — 51,415. Floaters for above, each £0. 0. 8 .... 2 0. 1. 4 51.414. Burettes with glass stopcock, 100 ccm . 1 0. 4. 8 51,342. Measuring glass with stopper, 250 ccm 1 0. 2. 5 51,341. Measuring cylinder with lip, 100 ccm . 1 0. 1. 3 200 ccm .... 1 0. 1. 7 1 0.1. 500 „ .... 1 0. 2. 3 1000 „ . . . . 1 0. 4. 1 51,379. Measuring flasks, with stoppers, 100, 250, 500 and 1000 ccm 4 0. 4. 2 4 0. 4. 51,411. Overflow pipettes, 2 of each size of 1, 5, 10, 25 and 50 ccm . 10 0. 5. 0 10 0. 5. 51.352. Porcelain dishes, 2 each of 60, 70, 85, 100, 125 and 155 mm 12 0. 4. 0 idem, 260 mm . . 2 6. 4. 0 Porcelain dishes, 2 each of 70, 100 and 155 mm — 6 0. 2. Small porcelain dishes for combustion experiments, 42 mm of diam 10 0. 1. 6 51.353. Porcelain cru- cibles, 2 sets .... 16 0. 8. 8 idem, 30 ccm alone 3 0. 1 . Glowing capsules of porcelain .... 5 0. 3. 0 — Glass rods, up to 10 mm thick ... 0,5 kg 0. 0. 10 0,5 kg 0. 0. Sieve-plates of por- celain, 40 mm ... 1 0. 0. 5 — idem, of 70 mm . 1 0. 0. 8 Sieve-funnel of porcelain, 80 mm . 1 0. 0. 7 idem, 125 mm . . 1 0. 1. 0 ">!.: :!49. Watch glasses. ? each of 50, 65, 80 and 100 mm .... 8 0. 2. 6 ol.'?50. Watch glass clamps, 1 set ... 4 0. 1. 3 Glass bell with flat stopper 300 mm high, 120 mm diam 1 0. 3. 7 300 mm high, 150 mm diam 1 d. 4. 5 250 mm high, 100 mm diam 1 0. 2. 10 150 mm high, 80 mm diam 1 0. 1. 7 i 'ylinder with foot and brim 200 mm high, 50 mm diam 2 0. 1. 4 300 mm high, 50 mm diam 2 0. 1. 7 400 mm high, 80 mm diam 2 0. 3. 8 250 mm high, 80 mm diam. . 2 0. '2. 5 — 10 I - For For Eealanstalten Gymnasia Number £ s. d. Number £ s. d. — Cylinder with wide neck and ground-in stopper 250 mm high, 80 mm diam 2 0. 300 mm high, 60 mm diam 3 0. 200 mm high, 60 mm diam 2 0. 130 mm high, 40 mm diam 2 0. Glass plate, round, matt on one side 20 cm 1 0. 0. 7 — Joining stopcocks, 3 mm outlet .... 2 0. 3. 0 2 0. 3. 0 Three-way-cock, 3 mm outlet .... 2 0. 6. 4 2 0. 6. 4 Three-way-piece with 2 stopcocks . . 1 51,174. Brass tap with hose pieces .... 1 51,168. T -piece for hose 1 4. 6 — — 5. 0 — 2. 9 — 1. 4 — unions 51,17d. + -piece for hose connections .... 51,256. Gasometer of glass, 15 litres capacity . . 51,253. Gasometer (Pepys'; 50 liters capacity 51,282. Gas generating apparatus (Kipp's), 1000 ccm 51,403. Gas washing flasks (Bunsen's), 500 ccm Separatory funnel, 50 ccm idem, 150 ccm . . 51,407. Spherical tubes, 2 sets 51,409. U- tubes (desiccat- ing tubes), 2 each of 80, 130 and 180 mm idem, 210 mm . . Test glasses, cups, 50 ccm 100 ccm Mercury trough, 300 ccm, of porcelain Double-shelled flask (Dewar's), 200 mm long, with foot 51,339. Pneumatic trough 51,322. Pulverising dishes, 70, 100 and 130 mm idem, 70 and 130mm 5 1 ,320. Mortar with pestle 51.355. Flat iron dish, 80 mm .... 51.356. — 100 mm . 51.357. -- 150 mm . Iron tubes, 50 cm long, 2 cm wide, open Iron tube, 40 cm long, closed at one side_ Total ." 0. 0. 0. 0. 4. 0. 0 1 0. 0. 0. 2. 0. 2. 0. 0. 2. 0. 0 3. 0. 0 — 1. 0. 0 — 0. 3. 0 — 4. 0 — 2. 0 — 1 0. 5. 5 — — h 1 1. 0. 0 1 1. 0. 0 s, i 3 0. 3. 5 m - — 2 0. 2. 4 le 1 0. 15. 0 — — 1 0. 0. 4 1 0. 0. 5 — — . . 1 0. 0. 7 — — n ft 2 0. 2. 6 — — [1 le 1 0. 7. 0 — — £ 28. 9. 10 £ 6. 4. 7 Various supplies and tools. Wall board and tool cup- board with tools for general use see in the collections of fittings for the Physics and Chemistry class- rooms, vol. I. 51,309. Crucible tongs, polished 3 — Tweezers, of iron. 1 0. 3. 0 1 0. 0. 5 — 0. 1. 0> 69 1090 Estimates of Cost for Chemical Supplies. For Realanstalten For Gymnasia Number £ s. d. Number £ s. d. 51,319. Phosphorus spoon, of iron 3 0. 1. 0 — Spoon of glass, with spatulum ... 3 0. 2. 6 Horn spoon with spatulum, 150 mm long 1 0. 0. 5 — 180 mm long . . 1 0. 0. 6 — — 220 mm long . . 1 0. 0. 9 — — Casting ladle, 50 com 1 0. 0. 6 — 200 , 1 0. C. 9 — 51,325. Blowpipe .... 1 0. 1. 0 1 0. 1. 0 51,331. Cork boring ap- paratus with 8 steel piercers 1 1. 0. 0 — 51.334. Sharpener for cork-borers .... 1 0. 1. 6 51.335. Cork press ... 1 0. 3. 6 52,547. Hydrometers, for heavy and light liquids 2 0. 4. 0 — Glazier's diamond 1 0. 4. 0 — Cracking coals . . 10 0. 1. 0 10 0. 1. 0 — Glass tongs ... 1 0. 2. 0 1 0. 2. 0 — Brush for small beakers 1 0. 0. 9 — Brushes for large beakers 1 0. 1. 6 1 0. 1. 6 Brush for test glasses 1 0. 0. 5 — Glass knife with handle 1 0. 1. 3 Iron spatulum, 210 mm long ... 1 0. 0. 6 1 0. 0. 6 Mortar-cleaner of horn, 60 mm ... 1 0. 0. 1 100 mm 1 0. 0. 3 — Capsulator, 90 mm long 1 0. 0. 5 — 120 mm long . . 1 0. 0. 6 Casting mould for bars, cast iron ... 1 1. 5. 0 Planed cast iron plate, 20 x 25 x 2 cm 1 0. 5. 0 Hammer for mine- ralogical purposes . 1 0. 2. 0 — — Total ... £ 4. 4. 6 £ 0. 7. 0 Materials, Chemicals, Bottles and Boxes. 50,947. Steel flask (bomb) for 1000 litres oxygen 1 1.16. 0 , 50,948. Oxygen charge . 1000 1 0. 10. 0 50.951. Foot board for oxygen cylinders . . 1 0. 5. 0 50.952. Lever key for oxygen flasks ... 1 0. 6. 0 51,292. Mercury, chemi- cally pure 5 kg 2. 0. 0 3 kg 1.4. 0 ."> 1 .295. Mercury box, 3 kg capacity 1 0. 6. 0 1 0. 6. 0 51,402. Filter paper, me- 100 | ft ,r 100 \ n ,o dium thick . . .sheets/0'13 ° -•— * ~> White blotting paper for washing .r>l,401. Hardened filters, 11 cm diam 20 0. 1. 2 — Parchment paper . 0. 0. 6 Parchment tube, 5 cm wide 2m 0. 0. 7 Watch springs for burning in oxygen . 20 0. 2. 0 Bteefflask for 10kg carbonic acid ... 1 1. 16. 0 — — Charge of carbonic acid 10 kg 0. 12. 0 Cloth bag for solid carbonic acid ... 1 0. 3. 0 Asbestos wool, BB- IH-SIII- paper .... 1 kg 0. 2. 0 — Glass wool ... 100 g 0. 3. 0 — Hollow glass peai Is loo 0. 3 (• sheets/ sheets j 1000 ) , 2 0 100° \ 1 2 sheets/ l< - u sheets/ ' Solid Reagents for Demonstrations and Laboratory Use. (The figures given indicate size of bottle in crm. The Collection for Gymnasia contains only the sub- stances marked *). For Colleges For Grannar Schools No. £ s. d. No. £ s. d. 145 18. 15. 0 30 3. 15. o 500 H202 Hydrogen Superoxide (3%) *500 S Sulphur *300 S Flowers of Sulphur 300 HjBO, Boric Acid 300 Na-B,'O, Borax 300 C " Graphite *300 C Charcoal 300 C Animal Charcoal 300 C Burnt Black *300 CS2 Carbon Bisulphide 50 Fluorescein 50 Phenolphtalein 50 Methyl Orange *100 Br Bromine 100 KBr Potassium Bromide *100 I Iodine 100 I Tincture of Iodine 100 KI Potassium Iodide 100 Potassium Iodide Starch Paper 10. 1. 3 3. 5. 0 200 HF1 \ Rubber flask / 500 Si02 *300 P \ dark glass / 300 P 100 As 100 As2O3 100 Sb 100 SbS 100 300 300 *300 50 *100 *300 300 500 KMgCl3 300 100 K 300 KC1 *300 KOH 300 CyK 300 K2S 300 KCyS 500 KNOa 300 KNO2 300 K2S04 300 KHSO4 500 K2C03 •500 KC103 300 100 K2Cr04 500 KaCrjOj *500 Na *500 NaCl 500 NaCl 300 NaOH •500 Na2C03 500 Na2C03.10H20 500 Na2S04.10H20 300 HNaSO., 300 NaCjH.,0.. *500 Na.jS.jO., 500 NaNO, 300 300 Na.HP04 *500 CaO 500 (NH4)(NO3) 300 NaHCO3 *500 (NH,)C1 500 300 800 300 100 (NH4),Cr,O, Fluorsilicic Acid Fluoric Acid Kieselgur Phosphorus, white Phosphorus, red Arsenic White Arsenic Antimony Antimony Sulphide Tartarised Antimony Glycerine Oxalic Acid Starch Indigo Litmus Sugar Paraffin Wax Carnallite Rochelle Salt Potassium Potassium Chloride Caustic Potash Potassium Cyanide Potassium Sulphide Sulphocyanide of Potassium Potassium Nitrate Potassium Nitrite Potassium Sulphate Potassium Bisulphate Potassium Carbonate Potassium Chlorate Potash Soap Potassium Chromate Potassium Bichromate Sodium Sodium Chloride, purr Common Salt Sodium Hydrate Sodium Carbonate Soda Crystals Sodium Sulphate Sodium Bisulphite Sodium Acetate Sodium Thiosulphate Sodium Nitrate Sodium Oleinate Sodium Phosphate Burnt Lime Ammonium Nitrate Sodium Bicarbonate \nimonium Chloride Ammonium Carbonate Ammonium Molybilate Sodio-Ammonic Phosphate Ammonium Dvalate Ammonium Bichromate Estimates of Cost for Chemical Supplies. 1091 300 Ca 500 CaS04 500 CaC03 500 500 CaClj 500 500 CaC2 300 BaCl. 300 Ba(OH)2 300 BaO2 300 Sr(OH) 300 Sr(N03)2 300 Mg *300 Mg *300 Mg 500 MgSO,.7HoO *100 Al 100 Al 100 Al *100 Al 100 A12(S04)3 Metallic Calcium Burnt Gypsum Chalk, powdered Soda Lime (granular) Calcium Chloride (granular) Chloride of Lime Calcium Carbide Barium Chloride Barium Hydroxide Barium Superoxide Strontium Hydrate Strontium Nitrate Magnesium Magnesium Tape Magnesium Powder Epsom Salts Aluminium Aluminium Wire Aluminium Powder Aluminium Foil Aluminium Sulphate *500 A12K2(S04)4.24H20 Potassium Alum. Ferric oxide *300 Fe 500 FeS04 500 FeS 300 K3Fe(CN)6 300 K4Fe(CN)e 300 Ni 300 NiS04 50 Mn 300 MnSOj *300 Mn02 300 Zn 300 Zn 300 ZnO 300 ZnS04 100 Cr203 100 Cr 100 Cr03 50 Co 50 CoCl2 50 Co203 *300 Cu *300 CuO *500 CuS04 100 100 300 CuCl2 300 PbO 300 Pb02 300 Pb3O4 300 Pb(N03), 300 (CH3COO)2Pb 100 Hg 100 HgCl2 100 Hg2Cl2 \ (dark glass) / 100 HgJ2 100 HgS *100 HgO \ (dark glass) / 50 Cd 50 CdS04 50 Ag 50 AgN03 \ (dark glass) / 50 Bi *300 Sn 300 SnCl2 300 300 Pt 300 Au Iron (powdered) Ferrous Sulphate Iron Sulphide Potassium Ferricyanide Potassium Ferrocyanide Nickel, sheet and wire Nickel Sulphate Manganese Manganous Sulphate Manganese Dioxide, granular. Zinc (granular, pure) Powdered Zinc Zinc Oxide Zinc Sulphate Chromic Oxide Chromium Chromium Trioxide Cobalt Metal Cobalt Chloride Cobalt Oxide Copper (granular, porous) Cupric Oxide (granular, porous) Copper Sulphate Bremen Green Schweinfurt Green Cupric Chloride Lead Oxide Lead Superoxide White Lead Lead Nitrate Lead Acetate Mercury Calomel Mercuric Chloride Mercuric Iodide Cinnabar Mercuric Oxide Cadmium Cadmium Sulphate Silver, sheet Silver Nitrate Bismuth Tin (rods and foil) Stannic Chloride Pink Salt Platinum Sheet Gold Sheet 51.370. Bottles for solid chemicals, 50 ccm ca- pacity, with wide openings, enamel labels, burnt-in black inscrip- tion and flat stopper. The inscription con- sists generally of the chemical formula and the designation . . 12 51,370. 100 ccm .... 29 51,370. 300 „ .... 68 51,370. 500 „ .... 31 51,370. Bottles of dark glass for solid chemi- cals, 50 ccm capacity, with wide openings, enamel labels, burnt- in black inscriptions and flat stopper . . 1 51,370. 100 ccm .... 2 51,370. 300 „ .... 1 Caoutchouc bottle for HF1, 200 ccm 1 For For Realanstalten Gymnasia Number £ s. d. Number £ s. dr. 1. ll. 5 4. 16. 4 2. 12. 11 5 13 10 0. 5. 5 0. 18. 5 0. 17. 1 1. 1 2. 10 0. 1. 7 0. 0. 1. 5 1. 7 4. 0 — — Liquid Chemicals . 49 7. 10. 0 12 0. 18. 0 500 NaOH \ (rubber stopper) / 500 NaOH 500 KOH \ (rubber stopper) / *500 H3N HCl HC1 HCl HNO3 HN03 HNO, *500 *500 500 •500 *500 500 500 H..SO, 0. 12. KI KCyS (NH4)2S K2CO3 Na2SO, Na2C03 Na2SO3 500 H..S04 500 H2SO4.S03 500 (CH3)(COOH) 500 HoO2 500 CS"2 " *500 C2H6OH 300 C5H,,OH *300 C,,H10N202 *500 (C,H,)20 *500 300 100 300 300 300 500 300 300 300 CH3COONa 300 KCiO 300 NH4C1 300 CaCl, 300 300 K2Cr20, 300 KMnO4 300 FeCl3 300 ZnSO4 *300 CuSO4 300 HgCl2 300 Hg2(N03)., 300 Pb(NO3)., 100 PtCl, 100 N03Ag \ (dark glass) / 300 100 CdS04 *500 *500 500 Caustic Soda Sodium Hydroxide, normal Caustic Potash Liquor Ammonii Muriatic Acid, crude Muriatic Acid, pure Muriatic Acid, normal Nitric Acid, crude Nitric Acid, pure Nitric Acid, fuming Sulphuric Acid, pure Sulphuric Acid, dilute Sulphuric Acid, fuming Acetic Acid Hydrogen Superoxide (3%) Carbon Bisulphide Alcohol Amyl Alcohol Indigo Solution Ether Litmus Solution Potassium Iodide Potassium Sulphocyanide Ammonium Sulphide Potassium Carbonate Glauber Salts Soda Sodium Sulphite Water Glass Sodium Acetate Eau de Javelle Ammonium Chloride Calcium Chloride Ammonium Molybdate Potassium Bichromate Potassium Permanganate Ferric Chloride Zinc Sulphate Copper Sulphate Mercuric Chloride Mercurous Nitrate Lead Nitrate Platinous Chloride Silver Nitrate Tannic Acid Cadmium Sulphate Benzine (petrol) Petroleum Soap Solution 51,370. Bottles for liquids, 100 ccm capacity, with narrow neck, enamel label, burnt-in black inscription and flat stopper .... 51,370. — 300 ccm . . . 51,370. — 500 „ . . . 500' „ with rubber stopper . . . 3 22 21 0. 3. 3 1. 11. 2 1. 15. 10 o 10 0. 2. 10 0. 17. 1 0. 3. 5 — 69* 1092 Estimates of Cost for Chemical Supplies. 0. 12. 0 — — 0. 6. 0 — — For Roalsantalten For Gymnasia Number £ s. d. Number £ 8. d. 51,370. — 2000 com, store bottles for hydro- chloric acid, crude, normal, pure and sul- phuric acid .... 51.370. — 5000 ccm, for aqua destillata . . . 51,370. Bottles of dark glass for liquid chemi- cals, 100 ccm capacity, with narrow neck, enamel label, burnt-in black inscription and flat stopper .... 51,370. Store bottle with wide opening, glass stopper, 1000 ccm ca- pacity, for burnt lime — Store bottle with wide opening and cork stopper, 2000 ccm ca- pacity, for NaCl — so- dium chloride . . . — • Store bottle with narrow neck, with cork stopper, 2000 ccm for lime water . . . Boxes of sheet me- tal, 1000 ccm, with label, for cuttings of sheet-zinc, pieces of marble, cement, clay, sand 6 0. 9. 0 — Collection of Organic Chemicals. — Solid Chemicals 32 4. 5. 0 0. 1. 3 — — 0. 2. 1 — — 0. 3. 3 — — 0. 3. 0 — 300 Oxalic Acid 300 Tartaric Acid 300 Citric Acid 300 HgCy2 300 Urea 300 Hydroquinone 100 Picric Acid 100 Pyrogallic Acid 300 Benzoic Acid 100 Salicylic Acid 500 Grapo Sugar 500 Crude Sugar 300 Honey 300 Lactose .500 Starch 300 Gun-cotton 51,370. Bottles for solid chemicals of the orga- nic collection, 50 ccm capacity, with wide openings, enamel label, burnt-in black inscrip- tion and flat stopper 5 5L370. — 100 ccm ... ., 57.310. — 300 „ . . . 21 51,370. — 500 3 300 Collodion Wool 50 Fuchsine 300 Naphtaline 300 Anthracene 50 Alizarine 300 Paraffin Wax 300 Camphor 300 Common Rosin 300 Wax 300 Shellac 300 Tallow 300 Cocoanut Oil 300 Glue 5C Morphia 50 Quinine 50 Cafein Liqird Chemicals . 27 300 CHC1.. Chloroform :in:i CH.,o"lI Methyl Alcohol 300 CH2O Formaldehyde 100 CHOOH Formic Acirt r.oo C., 11,01 1 Alcohol 100 Aldehyde 300 Acetic Acid 500 Ether inn Nitric Ether 100 Acetic Kther 300 Amyl Alcohol Inn Amyl Acetate 100 Lactose 500 Glycerine < . 5. 0 — 0. 3. 3 1. 9. 9 0. 5. 1 3. 0. 0 300 Benzene 300 Toluene 300 Nitrobenzene 300 Aniline 300 Phenol 300 Creosote 300 Toluidene 300 Terpentine Oil 300 Bone-oil 300 Olive Oil 300 Linseed Oil 50 Clove Oil 50 Oil of Citron For Realanstalten For Gymnasia Number £ s. d. Number £ s. d. 51,370. Bottles for liquid chemicals of the or- ganic collection, with 2 0. 2. 0 (i 0. 6. 6 16 1. 3. 6 3 0. 5. 2 — inscription, 50 ccm 51,370. -- 100 ccm . . , 51,370. — 300 „ . . 51,370. — 500 „ . . Total £ 63. 3. 11 £ 11. 1. 10 4. 4 — Tubing, Wires, Terminals, Stoppers. 51.154. Flexible leads, 2,5 sq. mm, 60 cm long 2 0. 2. 6 51.155. - 90 cm long .2 0. 3. 0 51,157. — 150 cm long . 2 0. 51,163. Rubber tubing~ No. 2/0 2m 0. 0. 6 „ No. 1/0 2m 0. 0. 8 No. 3 2 m 0. 2. 4 2 m „ No. 6 2m 0. 3. 4 51,165. Rubber tubing, gray, for connecting up gas burners . . 51,336. Rubber stoppers, 2 each of 16, 18, 20, 23, 25, 28, and 30 mm without holes ... 14 51,336. Rubber stoppers, with holes, 16, 18, 20, 23, 25, 28 and 30 mm 14 60,172. Foot or stand clamps (Holtz's) . . 3 61,093. Terminals for con- necting two wires . 3 61,098. Terminals for strips and wires . . 5 0. ~2. 1 1 — Pinch cocks ... 3 0. 0. 11 0. 18. 0 — 0. 2. 4 6m 0. 6. 0 3 m 0. 3. 0 0. 4. 9 14 0. 4. 9 0. 5. 4 14 (). 5. 4 0. 1. 0 — Total . £ 2. 15. £ 0. 15. Apparatus for General Use. 51,233. Water bath with m constant level ... 1 0. 18. 0 Asbestos air-baths after Junghahn . . 4 0. 10. 0 Drying closet of £! copper, 25 x 15 x 15 cm 1 1.10. 0 51.397. Desiccator (Fre- senius') 1 0. 4. 0 51.398. — (Scheibler's), with porcelain inset 2 0. 10. 0 51,537. Analytical balance without iron or steel Earts, with aluminium earn, rider slide, glass case agate planes, to carry 200 grams, sen- sitivity 0,2 mg ... 1 8. 10. 0 51,581. Hydrostatic ba- lance, to carry 1 kg 1 3. 10. 0 51,625. Analytical weights, 1 mg to' 200 g ... 1 set 1. 17. 0 51,637. Rider weights . 1 set 0. 5. (> 51,651. Precision weights, 10 mg to 1000 g . . 1 set 0. 17. 0 54,097. School spectrum • apparatus 1 4. 10. 0 54.129. Glass tul.es with platinum lugs ... 12 0. (i. o 54.130. Stands for holding the glass tubes . . 2 0. 8. 0 54,214. 10 Reagents for spectrum experiments 10 0. 15. 0 Estimates of Cost for Chemical Supplies. 1093 Number 54,400. Microscope with optical outfit for 60 to 1400 diameters, joint fo- tilting coarse and fine tube focus- sing, illuminating ap paratus with iris aia- phragm, with triple revolving nose-piece 54,850. Demonstration thermometer .... 54,859. Cylindrical thermo- meter for — 20 to + 360° C — Cooler, Liebig's, 300 mm long . — 500 „ Crucible of nickel, with covering, 25 ccm Crucible of quartz glass, transparent, with covering, 25 ccm Crucible of platinum, with covering, 12 ccm capacity, 12 g weighing Platinum wire, 0,35 mm, piece of 300 mm - 0,25 mm, piece of 300 mm . . . Sheet-platinum, 40 x 40 x 0,03 mm Spongy platinum . Platinum asbestos 10 g Total For Eealsantalten For Gymnasia £ s. d. Number £ s. d. B Z 1 15. 0. 0 * 1 IO- 0. 6. 0 — 1 0. 3. 0 — 1 0. 1. 11 — 1 0. 2. 5 1 0. 2. 5 n 1 z 0. 2. 6 1 0. 2. 6 i 1 m, 0. 5. 0 '— i ng 1 K 4. 10. 0 — — o n 1 0. 5. 6 1 0. 5. 0 e 1 0. 3. 0 1 0. 3. 0 1 0. 8. 0 — 0. 2. 0 s 10 g 0. 12. 0 — £ 46. 11. 10 £ 0. 13. 5 1. 0. 0 — — 2. 6. 0 — — 3. 15. 0 — — 0. 3. 0 — — Apparatus and Supplies for definite experiments. 62,183. Voltameter . . . 62,220. Hofmann's appa- ratus, one with pla- tinum electrodes, an- other with carbon electrodes Apparatus for ana- lyzing gases (M. T., Fig. 241) with phos- phorus pipette, 2 simple gas pipettes, 1 combined gas pipette Apparatus for de- monstrating the in- crease of weight of a burning candle . . Igniting tubes (M. T., Fig. 250) .... School apparatus for generating elec- trolytically hydrogen or oxygen (Ztschr. 2. d. phys. u chem. TJ. 23, 1910, p. 284) . . Apparatus for the electrolytical disen- gagement of chlorine (M. T., Fig. 248) . . Mercury gas-mea- suring bell (Ztschr. f. d. phys. u. chem. U., 23, 1910, p. 287) . . 51,246. Calibrated gas bells, 500 ccm . . . 0. 4. 0 0. 18. 0 1 0. 12. 0 0. 12. 0 1. 12. 0 — 0. 16. 0 Total £ 11. 6. 0 £ 1. 14. 0 Supplies for Pupils' exercises in chemistry after Prof. Schaefer, Recklinghausen (for 8 work places). Number per place £ s. d. Iron support 1 0. 1. 10 — Iron support rings 3 0. 2. 3 Clamp with double socket . . 1 0. 2. 8 Retort holder with double socket 1 0. 3. 3 Three-sided file 1 0. 0. 11 Number per place £ s. d. 51,163. Rubber tubing, 5 mm aperture 1m 0. 1. 2 Pinch cock 1 0. 0. 3 51,165. Rubber tubing for connecting gas burners 1m 0. 1. 0 51,186. Bunsen burner 1 0. 2. 6 51,192. Slit annex 1 0. 0. 9 51,220. Tripod, iron, 100 mm diam. . 1 0. 1. 0 51.226. Wire net of iron 2 0. 0. 8 51.227. Wire net of brass . . . .' 1 0. 0. 5 51,308. Iron crucible tongs 1 0. 0. 10 Test glass holder, sheet brass with slider 1 0. 0. 4 Horn spatulum, 12 cm .... 1 0. 0. 4 Iron spatulum, 18 cm .... 1 0. 0. 4 — Clay triangles, 40 x 60 mm sides 2 0. 0. 5 51,322. Pulverising dish, 100 mm diam. 1 0. 1. 1 51,325. Blowpipe 1 0. 1. 0 51,341. Measuring glass, 100 ccm . . 1 0. 1. 3 51.345. Beakers, 1 set 8 0. 1. 9 51.346. General test glasses, 150 x 16mm 10* 0. 0. 6 Test glasses of refractory glass 2 0. 0. 6 51.347. Test glass stand for 12 glasses 1 0. 1. 6 51,349. Watch glasses, 65 mm .... 3 0. 0. 9 Clamp for same 1 0. 0. 5 Sand bath dish, 15 cm diam. . 1 0. 0. 7 51.352. Porcelain dishes, 60,70and 85mm 3 0. 0. 8 51.353. Porcelain crucibles, 65ccm capacity 1 0. 0. 6 51.368. Powder jars. 300 ccm .... 4 0. 2. 0 51.369. Bottles for liquids, 300 ccm . 2 0. 0. 9 51.370. Bottles for chemicals, 150 ccm, with inscription 12 0. 14. 6 1. HC1 cone., 2. HC1 diJ., 3. H2S04, cone., 4. H2SO4 dil., 5. HN03, 6. Na2 CO3, 7. (NH4)2S, 8. KOH, 9. Na2HP04, 10.(NH4)OH, 11. Bad., 0. 4. 0 0. 18. 0 51,376. Boiling flasks, 1 each of 100, 250, 500 ccm 3 0. 0. 8 51,382. Retorts without tubes, 100, 250, 500 ccm 3 0. 1. 0 51,383. Retorts with tubes, 100, 250 ccm 2 0. 1. 1 51,389. Funnels, 50 and 80 mm . . . 2 0. 0. 4 51,391. Safety funnel 1 0. 0. 5 51,400. Spray flask, 250 ccm, with cork stopper 1 0. 0. 7 51,406. Bent tubing 'Akg 0. C. 6 51,410. Stirring rod, 25 cm long . . . 0. 0. 3 Litmus paper, blue and red . . 0. 0. 5 Glass plates 4 0. 0. 7 Refractory glass tube, 25 cm long 1 0. 0. 6 - U-tubes (desiccating tubes) 100mm 2 0. 0. 6 Brush for test glasses .... 1 0. 0. 6 Filter paper ] 0 sheets 0. 0. 6 — Charcoal 0. 0. 4 Stoppers of caoutchouc and cork 1 set 0. 4. 0 1 place £ 3. 0. 10 Supplies for 8 places 8 24. 6. 8 51,370. Store bottles for the chemicals, 1000 ccm, with inscription . . . 12 1. 5. 0 Spare chemicals for pupils' exer- cises, the materials as above . . 12 0. 18. 0 Total . .£29. 10. 6 Grand Total of Collection 6. For Real- For Gym- anstalten nasia Stands, Small Tables, Supports . . 5. 18. 7 3. 18. 11 Buiners and accessories ...... 11. 1. 11 3. 5. 8 Hollow wareof glass,porcelain,clayetc. 28. 9.10 6. 4. 7 Divers kinds of supplies and tools . 4. 4. 6 0. 7. 0 Materials, chemicals, bottles and boxes 63. 3.11 11. 1.10 Tubing, wiring, terminals, stoppers 2. 15. 7 0. 15. 5 Apparatus for general use .... 46. 11. 10 0. 13. 5 Apparatus and supplies for determi- nated experiments 11. (i. 0 1. 14. 0 Grand total (without supplies for pupils' exercises) 173. 12. 2 28. 0. 10 Supplies for pupils' exercises, for 8 work places 29. 10. 6 — Grand total with supplies for pupils' ~ exercises £ 203. 2. 1094 Physical Apparatus for Projection. Physical Apparatus for Projection. This collection replaces and cancels that given in Vol. I, pp. 190 — 192. The following pages contain a list of those pieces of physical apparatus which are used in conjunction with -the projection lantern. Further details as to these illustrations, references to literature on the subject etc. are to be found in this sams catalogue under the respective list numbers. We hold a large selection of photographs, diapositives, microscopical preparations etc. When requiring such, we should be glad if application be made for our complete list of these, stating in connection with which branch of the sciences the photographs and preparations are chiefly desired. Projection lanterns, accessories and auxiliary apparatus for projection purposes (for projecting horizontal objects etc.) see vol. I of this list which will be sent on request. Measurement of Lengths, An?les, Introduction. 51.423. Linear vernier model, with forward vernier 1. 5. 0 51.424. — idem, with rear vernier 1. 5. 0 51,488. Circular vernier model 1. 5. 0 51,750. Divisibility of fuchsin 0. 2. 0 Mechanics. 52,131. Foucault's pendulum experiment after Edelmann 62,138. Harmonic vibrations 52.588. Jet of water is composed of drops . . 52.589. Parabolic form of Water Jets 52.590. — idem, with 4 coloured discs, larger . 52,647. Piezometer after Weinhold 52,660. Plateau's apparatus 52,671. Demonstrating surface tension 52,675. Dropping apparatus for surface tension 52.677. Wide tube and capillary tube .... 52.678. — idem, for surface tension 52.679. 2 wide tubes with capillary tubes . . . 52.680. Wide tube with 5 capillary tubes . . . 52.684. 5 Different capillary tubes 52.685. Capillary tubes with plane parallel glass vessel 52.686. 5 Capillary tubes with stand 52.687. Capillary tubes alone 52.689. Behaviour of wetting and non-wetting liquids in a conical tube 52.688. 5 Capillary tubes of different shapes . . 52.690. Set capillary tubes 52.691. Migration of a mercury drop 52.692. Capillary plates 52.693. — idem, with stand 52.694. — idem, larger, with adjustable angle . Wave Motions. £ s. d. 9. 10. 0 2. 0. 0 1. 6. 0 0. 16. 0 2. 0. 0 2. 5. 0 1. 0. 0 0. 4. 0 0. 6. 0 0. 4. 0 0. 3. 0 0. 8. 0 0. 6. 0 0. 2. 0 0. 12. 0 0. 8. 0 0. 1. 0 0. 2. 0 0. 3. 0 0. 4. 0 0. 8. 0 0. 3. 0 0. 10. 0 0. 16. 0 53,150. Apparatus for Demonstrating wave 1 lf> 0 53,936. SO QQQ 53,151. Lantern slide for wave motions . Each 53, 1 53. Repulsion and Interference of wave motion 53,154. Adjustable mirror and bi-convex lens for 0. 1. 9, 1. 4. 5 6 0 0 53,940. 53,993. 53,995. 53 996 •> 8 0 KA (\f\f\ •> o 0 r.t nni 53,177a. — idem, with box for the glass discs. V$ 1 78 Wave machine after Crova •>. 9 5. 0 0 0 54.022. Acoustics. 53.263. Manornetrie Flame Pipe, afh-r Konig . 53,456. 2 Tuning forks, one with small pendulum, 1. 9 16. 191 0 0 54,026. 54,029. 20 64,030. 54,033. 64,036. 54,063. 53,519. Demonstrating the Lissajons curves . :.:i.:>24. — idem, by means of vibrating springs .V! .-,-'(; iHpm after Pfaundler . 4. 4. 1. 4. Iti. 4. 0 0 0 54,072. 64,073 ."14.074. Optics. 53.850. Tyndall's Drum 53.851. — with Mirror for total reflection . . . 53.852. Light-refraction apparatus after Mach . 53.853. Determining the refractive indices . . . 53.854. Optical demonstration apparatus, after Stromann 53.855. Laws of refraction, reflection, total reflection 53.856. — idem, with perfect circle 53.857. Reflection and refraction Apparatus . . 53.858. — idem, after Silbermann 53.859. Optical disc after Hartl 53.860. Addition for central pencils of rays . . 53.862. Polarisation apparatus to the optical disc 53.863. 4 Rapidly annealed glasses 53.864. Baseplate for crossed glasses : . . . . 53,864a. Projection lens 53,871. Light -refraction apparatus after Kolbe . 54,079. Transparent colour disc 53,746. Projection kaleidoscope 53,874. Light-refraction apparatus after Reusch 53,876. Apparatus for refraction in plane glasses 52,590. Apparatus for total reflection in a water jet (see section: Mechanics, £ 2. 0. 0). 52,589. — idem, smaller and without support (see section: Mechanics, £ 0. 16. 0). 53,883. Apparatus for total reflection in glass rods 53,881. 2 Glass plates for total reflection . . . 54.070. Spectrum and Fraunhofer lines .... 54.071. — idem, with larger prism and larger lens 53.935. Glass prism 53.936. Plate glass prism, 30 mm side .... Prism stand for above Plate glass prism, 50 mm side .... Prism stand 53.995. Crossed, prisms after Newton 53.996. Double prism on stand 54,000. Polyprism of five kinds of glass .... r>4.()04. Carbon disulphide prism Wernicke liquid priarn, 20 x 20 mm rture - idem, 45 x 45 mm aperture .... Direct-vision prism after Konigberger, •2~> x 25 mm aperture 54,030. — idem. 40 x 40 mm aperture Variable angle prism Prism apparatus with three prisms . . Crystal glass cone Apparatus with 7 mirrors - idem, with smaller mirrors — idem, with three mirrors 53.541. Tuning fork apparatus 13. 0. 0 53.542. — idem, for enabling compound parallel vibrations 15. 0. 0 53,544. Large tuning fork apparatus 18. 0. 0 53,552. 7 tuning fork curves on stand .... 1. 0. 0 53,577. 2 Massive tuning forks with resonator, for impact tones and Lissajous's curves . . . 27. 10. 0 2. 0. 0 2. 10. 0 3. 0. 0 2. 8. 0 8. 0. 0 4. 0. 0 4. 12. 0 5. 10. 0 8. 0. 0 3. 18. 0 1. 6. 0 2. 8. 0 0. 14. 0 0. 4. 0 0. 4. 0 9. 10. 0 1. 0. 0 1. 10. 0 0. 16. 0 d. (i. 0 1. 5. (I 0. 4. 0 3. 0. d 4. 0. 0 0. 2. 0 0. 5. 0 0. 18. 0 0. 12. 0 1. 4. o 2. 16. 0 1. 16. 0 •2. 10. 0 0. 16. 0 •2. 15. 0 8. 0. 0 1. 10. 0 2. 10. 0 •2. -2. 0 •2. 8. 0 1. 5. o I O. 0 3. 0. 0 1. 10. 0 Physical Apparatus for Projection. 1095 . . . 54.505. Newton's colour glasses, 70 mm diameter 0. 16. 54.506. — idem, 100 mm diameter 54.507. — idem, 120 „ 54.508. — idem, 150 „ „ .'.'.'•'.'.'. 54.509. Newton's colour glasses, with stand, rotary, 70 mm diameter 54.510. — idem, 100 mrn diameter . 54.511. — idem, 120 ,, 54.512. — idem, 150 „ „ \ 54.514. Interference Apparatus for Fresnel's mirror experiment, for projection apparatuses having 43 mm diameter objective .... 0. 4. 12. 12. 18. 2. 4. 2. 10. £ 8. d. •)4.075. Laminated mirror after Oosting .... 2. 10. 0 .-)L',043. Oscillating prism for the whirling table 1. 5. 0 52,044. — idem, larger 1. 10. 0 54.141. Collimator tube and micrometer gap for demonstrating the spectrum 1. 4. 0 54,144. Revolving device for arc lamps .... 1. 0. 0 50,922. 6 Cored carbons filled with salts ... 0. 9. 0 54,176. 6 Small flasks with absorbent liquids . 0. 10. 0 - idem, 9 liquids 0. 15. 0 54.178. — idem, 12 liquids 1. 0. 0 54,180. Absorption box, 55 x 35 x 10 mm ... 0. 3. 0 54,186. Hollow crystal glass cubes, 50 mm . . 0. 3. 0 54.190. Double absorption box 0. 12. 0 54.191. Absorption vessel, wedge-shaped .... 0 12. 0 54.194. Absorption vessel for gases 1. 10. 0 54.195. — idem, for filling with gases .... 0. 8. 0 54.196. Stand for holding absorption boxes, troughs, preparations 1. 0. 0 54.197. 3 Gelatine plates for absorption experi- ments 0. 2. 54.198. 3 Coloured glass plates 0. 3. 54.199. Coloured plate 0. 13. 54.200. — idem, simpler 0. 6. 51.201. Absorption colour plate for reflected light 0. 4. 54.202. 5 Crystal plates with absorption phenomena 2. 10. 0 54.225. Bunsen-burner for -eversing the sodium line 0. 14. 0 54.226. Stand with illuminating tube for reversing the strontium line 0. 16. 0 54.233. Solar spectrum, transparent .... 1. 0. 0 54.319. Apparatus for imitating the irradiation of the moon's crescent 0. 8. 0 54.320. Lantern slides after Plateau for demon- strating irradiation 0. 3. 0 54.324. Projection stroboscope 1. 0. 0 54.325. 3 Extra discs for above 0. 6. 0 54.326. Projection stroboscope with showing dancers 1. 4. 0 51.067. Cinematograph 7. 10. ft 51.068. Films for 1 metre length 0. 1. 6 54,32^. Anorthoscope 1. 6. 0 54.328. Apparatus for optical fatigue and the successive colour-contrast 0. 6. 0 54.331. — idem, after Weinhold 0. 10. 0 54.332. Apparatus for successive and simultaneous colour-contrast 0. 8. 0 54,3,,, .. 2 Coloured glass plates for simultaneous contrast . . 0. 6. 0 54,334. Apparatus for showing the contrasted colours as coloured shadows . . ... 0. 12. 0 54.338. Projection plate for optical illusions, showing parallel lines apparently diverging 0. 6. 0 54.339. 2 Plates for above, showing parallel lines apparently bent 0. 3. 0 54.340. — idem, four right angles are showing apparently acute and obtuse in pairs ... 0. 3. 0 54.343. 2 Plane parallel glass vessels for objec- tively demonstrating the colours of pigment mixtures 0. 16 0 54.346. 2 Colour discs for the mixing of coloured lights and the superposing of layers of trans- parent colours 1. 5. 9605. Projection chromoscope after Ives ... 13. 0. Photographs for above each 0. 7. 54,350. Colour top with mixed colour effects . 1. 0. 51.003. Small transparent projection screen . . 0. 10. 54.501. Small metal frame for soap solution for demonstrating the colours of thin plates . 0. 2. 4. 0. 0 £ s. d. - idem, having 55 mm diam. objective 4. 0. 0 54.516. — idem, having 60 mm diam. objective 4. 0. 0 54.517. Fresnel's apparatus, size of mirrors 30 x40 mm 2. 2. 0 54.518. — idem, size of mirrors 40 x 50 mm . 2. 8. 0 54.519. — idem, size of mirrors 50 x 60 mm . 3. 0. 0 54.520. Fresnel's apparatus, simple, size of mirrors 30 x 40 mm 1. 4. 0 54.521. — idem, size of mirrors 40 x 50 mm . 1. 12. 0 54,52<3. — idem, size of mirrors 50 x 60 mm . 2. 0. 0 54.523. Interference mirror on stand, with micro- meter motion 7. 0. 0 54.524. — idem, without micrometer motion . 4. 16. 0 54.525. Ocular micrometer after Fresnel .... 6. 0. 0 54,527. Interference apparatus after Grimsehl . 3. 10. 0 54,529. Interference apparatus after Classen . . 2. 10. 0 54.536. Interference Prism (bi-prism) after Fresnel 1. 8 0 54.537. Billet's half-lenses . . 2. 10. 0 54.538. Lens for observing the interference bands 0. 16. 0 54.540. Large bench for interference and diffrac- tion experiments 27. 0. 0 54.541. Diaphragmic disc with Schwerd apertures 1.10. 0 53.907. Cylindrical lens on stand, 60 mm diameter 1. 4. 0 53.908. — idem, 80 mm diameter 1. 10. 0 54.560. Photographed grating after Nobert . . 0. 18. 0 54.561. Copy of a genuine Rowland Grating . . 1. 4. 0 54.565. Photographed diffraction grating ... 0. 5. 0 54.566. Diffraction grating after Rowland. Price on application. Further diffraction gratings and stands see page 549. 54.575. Phase reversing plate, after Wood ... 0. 10. 0 54.576. Circular photographed grating 1. 0. 0 51,066. Projection diffraction -chromoscope, with optical bench 11. 10. 0 51,066a. — idem, without optical bench ... 10. 0. 0 54.584. Dust glass for colour rings 0. 4. 0 54.585. Reflecting stephanoscope after von Lommel 0. 16. 0 54.586. — idem, larger 1.6 0 52,047. Polarisation apparatus for the whirling table 1. 10. 0 54.590. Polarisation apparatus after Weinhold . 2. 8. 0 54.591. Further Set of Glass Plates, as polariser 0. 18. 0 54.592. Polarisation apparatus after Duboscq . 3. 12. 0 54.593. Polarisation apparatus on stand .... 4. 15. 0 54.594. Demonstration polariser after Grimsehl . 1. 2. 0 54.595. Demonstration analyser after Grimsehl . 1. 15. 0 54.596. Plate of mirror glass with haft . . . 0. 6. 0 54.597. Glass tube for polarisation in liquids . 1. 8. 0 54.598. Auxiliary apparatus for demonstrating the calc-spar cross 2. 0. 0 54.599. Demonstration polarisation apparatus after Grimsehl 1. 10. 0 54.600. Simple polarisation apparatus with tour- maline plates 3. 0. d 51,074. Polarisation apparatus for objective de- monstration 7. 0. 0 54.601. 1 Set of preparations 3. 5. 0 54.602. Large projection-polarisation apparatus after Duboscq and von Lang 34. 0. 0 54,614. Column of glass plates .... 1. 16. 0 54.626. Polarisation apparatus after Mach ... 13. 0. 0 54.627. Wedge compensator after Babinet ... 5. 0. 0 54.628. Compensator after Soleil 6. 10. 0 C4,634. Large Paalzow optical bench 34. 0. 0 54,635. Small Paalzow optical bench 16. 0. 0 Auxiliary apparatus referring to polari-\ sation and refraction, polarisation prepara-l., tions, spectrum phenomena, microscopical!, phenomena, interference and diffraction seel pages 559 — 561 J 54.641. Glass press for showing the double re- fraction by pressure 1. 2. 0 54.642. Fresnel's press 2. 15. 0 54.643. Glass bending press 1. 2. 0 54.654. Rapidly annealed glasses 2. 10. 0 54.655. Crossed annealed glasses 0. 10. 0 Preparations of gypsum, mica, calc-spar \ Prices as per and quartz see pages 564 — 566 | se'eclion 1036 Physical Apparatus for Projection. Heat. 54.788. Glass sphere with tube closed at top, for showing the expansion of liquids 54.789. — idem, with open tube 54.790. — idem, without filling for expansion of air 54,806. Apparatus for linear expansion of rigid bodies 54.819. Projection water dilatometer 54,827. Expansion-anomaly of water after Wais 54,832. Glass tube for circulation of water . . 54,837. Apparatus after Riihlmann for showing the expansion of water at constant pressure 54.854. 3 small thermometers with different liquids 54.855. Projection thermometer, divided from —40° to +50° C 54.856. — idem, divided from —10° to +160° C. 54.857. Projection thermometer with long stem, divided from 0° to +30° C., graduation Vio0 55,015. Freezing thermometer 55,036. Apparatus after Boutigny for the Leiden- frost experiment 55,090. Andrews' Press for compressing and lique- fying carbonic acid 55,123. Apparatus for the critical temperature phenomena 55,123a. Protecting case for above 55,254. Sectional model of a steam cylinder . . 55,291. Apparatus for demonstrating thermal conduction in metal rods 55,296. Apparatus for demonstrating the different thermal conductivity of copper, lead and wood 55,301. Gypsum slab for showing the elliptical propagation of heat in crystals 55,311. Apparatus after Despretz, for showing decrease of temperature with distance. . . 55,342. Small flat flask for filling with carbon bisulphide and Jodine 55.345. Plane parallel vessel for alum solution . 55.346. — the same, entirely of glass 55.347. Absorption of heat rays Magnetism. 60,072. Molecular magnet model 60,079. 2 Small magnets, 1 horseshoe and 1 bar magnet 60.082. Iron Powder, per 250 g 60.083. Sifter for above 60,089. Declination needle 60,096. Dipping circle 60.137. Magnetic pendulum, as suggested by Russner 60.138. -- The same apparatus, for placing on the optical bench of projection apparatus . Static Electricity. 60,186. Electroscope (v. Beetz's) 60,196. Aluminium electrometer (Kolbe's) '. . . 60,197 — 60,199. Accessories to the aluminium electrometer 60,202. Aluminium leaf electrometer (Grimsehl's) 60,203 — 60,205 and 60,208 — 60,210. Accessories 60.206. Graphite Conductor for demonstrating the potential drop in electric leads .... 60.207. — idem, with graduation 0. 1. 8 0. 1. 8 0. 1. 8 2. 10. 0 0. 7. 0 0. 8. 0 0. 8. 0 0. 12. 0 0. 16. 0 0. 6. 0 0. 6. 0 0. 12. 0 0. 7. 0 2. 0. 0 2. 4. 0 0. 6. 0 0. 12. 0 2. 6. 0 0. 12. 0 0. 14. 0 0. 5. 0 0. 16. 0 0. 1. 9 0. 12. 0 0. 5. 0 0. 16. 0 1. 16. 0 0. 5. 0 0. 1. 9 0. 1. 6 0. 9. 0 1. 4. 0 7. 10. 0 6. 5. 0 1. 2. 0 3. 0. 0 0. 16. 0 3. 10. 0 1. 18. 0 1. 10. 0 1. 17. 0 £ s. (1. Absolute Lecture Electrometer, as suggested by Braun, for projection, see No. 60,211 to 60,215 and 60,216. Volts 0—1500 0—1500 3500 graduated from IOC to 100 500 to 500 100 to 100 Volte £ 2.18.0 2.7.0 3.2.0 idem. Volts 3500 10 000 graduated from 500 to 500 500 to 500 Volts £ 2.10.0 3.12.0 60,217. Metal beaker for graduating 3. 0. 0 60,223. Pendulum electrometer (Weinhold's), for verifying Coulomb's law 4. 60.280. Leaf electrometer 2. 60.281. Accessories for graduating 2. 5. 8. 8. 60,283. — i d e m, by Faraday's" method . . . 0.16. 60,324. Standard condenser for aluminium electro- meter by Kolbe . . . .' 0. 18. 60,649. Repulsion apparatus (Puccianti's) ... 0. 16. Voltaic Electricity. 60,682. Zinc and copper plates for electrometer (Grimsehl's) (see Voltaic Electricity) .... 1. K.». <> 60.703. Pile electrometei 3. 5. 0 60.704. — idem, with open piles 3. 15. 0 60,739. Small projection cell (Kolbe's) 0. 8. 0 61,293. Vertical galvanpscope 1. 13. 0 61,384. Projection moving coil galvanometer . . 4. 0. 0 61,562. Demonstration of hot wire instruments after Scotti 1. 10. 0 62,115. Apparatus for showing the generation of heat by the electric current 0. 10. 0 62,188. Voltameter 0. 12. 0 62.216. Apparatus for objectively demonstrating electrolytic decompositions and crystalli- zations 0. 14. 0 62.217. Saturn's tree inset for above 0. 4. 0 62,231. Apparatus for electric endosmose ... 0. 10. 0 62.237. Migration of a drop of mercury by the inequality of surface tension produced electro- lytically 0. 8. 62.238. Capillary galvanoscope, after Weinhold . 0. 12. o 62,280. Electromagnet after Weinhold 2. 4. 0 62,365. Apparatus after Topler, for the existence of the magnetic curves 1. 4. 0 62,370. Explaining the lines of force theory after Berghoff (horizontal projection) 4. 0. 0 62,422. Apparatus for the rotation of liquid con- ductors (horizontal projection) 0. 12. (l 62,483. Showing damping by induction (hori- zontal projection) 0. 18. 0 62.903. Demonstration apparatus for rotating field experiments 6. 0. 0 62.904. 4 Glow wires for above 1. 0. 0 62,931. Apparatus for demonstrating the flow of current in three-phase conductors . . . 1. 10. () 63,443. Electrothermic apparatus after Schumann 1.12. 0 Divers Apparatus. 55.414. Radiophone after Weinhold 0. IS. o 55.415. — with a zinc sector disc 0. 14. 0 55.503. Rotary star chart 2. 0. 0 55.504. Universal clock 1. 8. 0 63,181. Electrometer for investigating radio- active substances 4. 0. o 63,183. Electrometer after Curie 6. 0. 0 Alphabetical Name and Subject-matter Index. 1037 Alphabetical Name and Subject-matter Index. Page Abbe, Indicating apparatus . . 537 Abbe-Listing, Refractive indices 479 Abbreviations VIII Aberration, chromatic . . . 488, 495 — spherical 495 Absolute electrometers 803, 804, 811, 841—844 - expansion of water .... 594 - vacuum-tube 1016 Absorbent liquids and colour plates 516, 517 Absorptiometer 411 Absorption boxes 516, 560 - colour plates 516, 517 — of coloured light . . . 516, 517 - of gases 411 - of heat 644—648 — of heat experiments with Kolbe's thermoscope . . . 596 - troughs and vessels .... 516 - vessel for experiments with Kolbe's thermoscope . . . 598 - vessel for polarisation appa- ratus 561 Acceleration and tension meter 257 - apparatus 257 Accessories for accumulators 857 — 861 - for aluminium electrometer 812 - for balances 240 - for franklinisation .... 822 - for gas burners 208 - for lecture tables see vol. I. - for microscopy 538 - for optical bench 472 - for projection apparatus see vol. I. - for quadrant electrometers 842, 843 - for reflecting galvanometers 878 Accessories for school galvano- meter 877 - for spectrum apparatus 511 — 518 - for vacuum pumps, . 400 — 402 Accessory apparatus for Kolbe's thermoscope . . . 595 — 598 — for Looser's thermoscope 589—504 Accommodation of the eye (Schei- ner's experiment) .... 524 Accumulator acid 857 Accumulators 854 — 857 - for measuring .... 930, 933 - for resistance galvanometers 586 Accumulator-switchboard . . 1073 Accurately ground mirror . . . 968 Acetylene gas burners, see vol I. — generators, see vol. I. Achromatic lens system .... 495 - prism 502, 503 Achromatised double refracting prisms 563 Achromats, Zeiss' 892 Acid for accumulators . . . .857 - proof black staining of table tops see vol. I. Acids and bases, mixed .... 625 Page Acoustic apparatus after Dvorak 463, 464 - after prof. Ebbinghaus 449 - attraction and repulsion . 463 - bellows 425, 426 - reaction wheel 464 Acoustics 418 — 464 Actinometer 651 Action of gunpowder 626 - of polarisers 847 - of water vapour 631 Adapter for connecting a number of thermometers 586 Additional accessories for Grim- sehl's electrometer .... 803 - apparatus for speaking arc lamp 1058 - series of tuning forks . . . 445 - voltage coils 903 Addition to optical disc . . 488, XV Additive and subtractive colour synthesis 528, 529 Adhesion 302 - and cohesion tube .... 405 - of non wetting liquids . . . 360 Adjustable gap 512, 545, 546, 560 - magnet system 959 - mirror and bi-convex lens 413 - rotary stage 503 - sounder 810 - stand for the lamp of Kolbe's thermoscope 596 - steel coherer . 1052 - tables 205 Aeolipile 630 Agate mortar 215 Air balloon experiments . 367, 368 - baths 210 - buoyancy 367 - chamber 366 - column, vibrating 433 - concussion apparatus . . . 419 - condenser 813 - plates 812 - displacement method for de- termining vapour density 614 - elasticity 366 - engines 629 - gun 410 • -ionisation 986, 1025 - is not heated by thermal rays 645 - pressure experiments 402 — 404 - pumps 386 — 399 - water exhaust pumps see vol. I. - reaction wheel . . . 404, 407 Airship propeller 357 Air tester 656 - thermometer 377 — 380, 581 — 584 - thermometer, demonstration 365 - thermometer, electric . . . 829 - thermoscope 567 - weighing 402 Airy, Double pendulum . 297, 451 Alarm clocks 244, 245 Al Biruni, Small flask and watch glass 345 Alcoholimeter 347 Alexander, Hydrometer .... 348 Page Alluard, Hygrometer 652 Alphabetical index 1097 Alternating action of currents and magnets 966—971 - -alternating current trans- former, see vol. I. - and three phase current 1000—1006 - charges and discharges of condensers 898 - current bell 961 - dynamos . . . 992 — 994 - motors 1006 - reflecting galvanoscope 892 - transformer 864, 1006 — 1008 - -direct current transformers, see vol. I. - gyroscopic tree 293 Alternator 1003, 1004 Altimetric thermometer .... 578 Altitudinal barometers. . 374 — 376 Aluminium and copper ring . . 1009 - dish 602 - egg after Thomson . . . .1004 - foil 814 - leaf electrometer .802, 809, 812 — electroscope 799, 800, 808, 812, 836 for atmospheric electricity 836 - lever 265 - ring and silk threads . . . 260 Alum slab 596, 597 Alvergniat, Air thermometer . . 582 Amalgam, Kienmayer's . . . 816 Amalgamated felt 797 - zinc plate 813 Amalgam-cells 1026 Amber, piece 814 American clamps 204 - freezer 214 Amici, Prism system 503 Ammeters 901 — 911 Ammonia tube 613 Ampere's Rule 968 - Stand 966 — 968 Amsler's Planimeter 230 Anaglyphon (plastoscope) . . . 529 Analogue for the charge and dis- charge of a condenser . . 336 Analysis of oscillatory discharge 837 - of the spectrum . . .499 — 518 Analyser after Delezenne 546, 564 Analysing apparatus for vibrations 300 Analytical balances . . . 231 — 233 Analytical weights ... 241, 242 Anatomical models 1069 Anchor escapement 333 Andrews, Calorifere 619 Andrews' Press for liquefying gases 608 Anemometer 658 Aneroid barograph ... 377, 651 - barometers 375 — 377 - for demonstrations . . 402 - thermoscope ....... 588 Angle lever 270 - apparatus 281 - mirror 475 See also the Subject-matter Index in vol. I. 1098 Alphabetical Name and Subject-matter Index. Page Angle mirror for Geissler tubes 1017 - for photometering glow lamps 470 - of altitude, measuring . . 483 - of elevation 263 - of incidence and of reflection in percussion experiments 303 - of incidence of light, mea- suring 465, 466 - of incident light and body colour 528 - of incident light and lumi- nous intensity 474 - measuring . .' . 228 — 230, 479 - of prisms determined . . . 479 - thermometer 578 - with obliquely placed tubes 281 Angular velocity and moment of inertia 290 - increases with decreasing moment of inertia .... 277 Annealed glasses 490 Annex for Bunsen burner . . . 208 Anomaly of water expansion . 573 Anorthoscope 526 Anschutz, Stroboscope 526 Ansell, Gas indicator 410 Anticyclones and antimonsoons, theory 286, 658 Anti-parallel cranks 314 Antiphone and telephone receiver 930, 935 Anti-vibration suspension . . . 885 See also vol. I. Antolik, Poly chord 441 - Riders of aluminium wire . 441 Aperture goniometer 466 Apostoli, Condenser bed, see special list Apparatus and instrument tables, see vol. I. - cupboards see vol. I. - for general use ... 201—220 — room (see Museum, vol. I.) - with mirrors 504 Apparently continuous light . . 287 Appendix 1072—1074 Apple Cutter 403 Appunn, Siren disc . . . 283, 420 Aiago and Biot, Gas prism . . 502 - Magnetism of rotation 287, 977 Aragonite 560 Arbor wheel .... 266, 270, 275 Arc, electric 406 Arc in vacuo . . 938 - lamp for proj ection apparatus, see vol. I. - mercury vapour arc lamp 515 — models 996 — — singing (whistling) . . 1058 — speaking . . 1057, 1058 — — -transformers, see vol I. - light after F. C. G. Miiller . . 473 — — for projection lamps, see vol. I. — hand regulator 1057, 1058 see also vol. I. — lantern 474 Archenhold, Explaining ebb and flow 661 Archiinedian law 343 - spiral disc 318 - water screw 357 Arco-Slaby, Wireless telegraphy 1050 Arc triangle 318 Arendt, Lecture tables see vol. I. - Metal strips 350 Argand burner for placing in the influence machine .... 825 — with slotted chimney . 843 Argon tubes •">'•"> Page Armatures of dynamos, explained 990, 991 Armillary sphere 662 Armstrong, Steam electric machine 816 Arno, Electrostatic rotary field motor 827 Aron's Tube 1044 Arrangement for hydrostatic tests 238 - for parallax-free reading . 1029 Arrhenius, Internal friction of li- quids 364 Arrhenius, Resistance vessel . .931 d'Arsonval's Apparatus . . . 1032 Arzberger and Zulkowsky, Air pump, see vol. I. Asbestos dishes 210 Ascension, capillary . . . 362 — 364 Aspiration psychrometer . . . 655 Aspirators 212, 213 See also vol. I. Aspirator action shown with Kol- be's thermoscope 598 Assay furnace, electric . 938 — 940 Assembled receiving station . . 1053 Astatic galvanometer 876 - magnet needles . 786, 787, 949 - mirror galvanometer . . . 883 Astigmatic test card 523 Astronomical telescope demon- stration 473 - and terrestrial telescopes 541—543 - eyepiece for telescopes. . . 543 — telescope, model 531 Asynchronism, demonstration 1004 Atmospheric electricity, electro- meter for 814 - electroscope for .... 836 Attachments for piezometers. . 359 Attachment with 3 disconnected tubes 281 Attraction, acoustic 463 — capillary 360 — of mass 300 Atwood's Fall machine . 253 — 255 Audibility limits 444 Audion 1052 Auditorium equipment see vol. I. Auer burner with slotted chimney 843 - lamp with reflector .... 539 August, Cup and ball 280 August, Psychrometer 654 Autogram disc, thermoscopic . . 600 Automatically singing arc lamp 1058 Automatic induction indicator . 971 — mercury vacuum pump . . 398 - needle coherer . . . . . 1051 — release 959, 1049 Auxiliary apparatus and accesso- ries to Kolbe's electrostatic apparatus 814 - for air pumps .... 402 - — for demonstrating the calc-spar cross 552 — — for generating solid air 610 - for influence machines 823—830 - for microscopes . . . .537 — — for Paalzow's optical bench 559 - for projection see vol. I. - for whirling table .280 — 289 - electroscope .... 802, 812 — outfit for Junkers' calori- meter 624 - parts for work stand 201, 202 tarardi V. \ I. Axes, stable and unstable . . . 282 Axial erc»s alter N'esller. . . 1066 Ayrton, Laboratory galvano- meter ....... . . 889 — Universal shunt. . . sss. ,s\-2 B Babinet, Fall chords 253 - Hydrometer 34S - Polariscope 556 - Vacuum pump stopcock . 387 - Wedge compensator . . . .V>(i v. Babo, Apparatus for elongation of paladium 853 - Gas generating apparatus . 213 Bach, Breaking model .... 30<> Back impact of outflowing liquids and gases 352 Bacteriology, laboratory table, see vol. I. Bag for photographic camera. . 522 - of rubber 212 Balance and sets of weights 231—244, XV — beam '21^ — chemico-technical 234 — 236, 623 — dynamic 252 — electric 804 - explained 270 - galvanometer 875 — gas balance 367 - magnetic 795 - pan 286, 310, 571 - Poggendorff's i>57 — with copper disc 1009 Ball bearing 302 - Gore's 627 - governor, Watt's 281 — Heron's 381, 382 — on double cord -if in — rotating IIHMI — valve 408 Ballistic galvanometers calibrated 976, 101-2 Balloons of collodion 368 Balloons of indiarubber .... 366 Balmain's Phosphorescent paint 520 Bamboo-stands with screens see vol. I. Band brake 252, 327 - spiral for magnetizing . .957 Bardeleben, Gas generating appa- ratus 213 Baretter set 933 Barium platino-cyanide, fluores- cent ."'lit — -platino-cyanide screens 986, 1027 Barker's Mill 353 Barlow's Wheel "-tin Bar machine sl.~i — magnets .... 785, 786. lo2.-> Baro-Hygrograph 651 - -1'sychrograph 651 - -Thermograph 651 Barometer 372—375 - demonstration . . . :>(>•'>, 371 — standing ln- — tubes . . . 370, 371, 602, (in:! Barometrical pressure gauge 370, (ill Baroscope 3<>4. .«o-_> Barrel's Fall apparatus .... Bars for pyrometers - of same weight 349 Base for measuring glasses. . .217 Baseplate for crossed glasses . 4!>O Bass fiddle how 1 In Batavian glass drops :!IJ Bathometer 3SO Battery alternating current a]>|>a r'atus 1001 See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1099 Page Battery box 886 - for high tension 811 — of accumulators. . . 855 — 857 - of Grove cells 853 - of Leyden jars . 832, 833, 1072 Bauernberger, Lines of force of cur- rent conductors . . 963, 965 Baume. Hydrometers 346 Baumhauer, Press for producing doublets 312, 566 Beakers 217 - with evacuated double walls 610 Beam with counter guide . . . 316 - without rotating axis . . . 316 Bearings for Nicol prism 557, 560 Beckley, Anemometer 658 Beckmann, Apparatus for molecu- lar weight determination . 615 - Mrtastatic thermometer . . 578 - Spectrum lamp 513 lamp demonstration table see vol. I. - Thermometer 615 Beclar, Kndosmometer .... 410 Becquerel, Phosphoroscope 285, 520 Beer, Double refraction .... 564 v. Beetz, Chronograph .... 256 - Electroscope 800 - Lecture galvanometer . . . 881 - Spark chronograph with tu- ning fork 248 - Tuning fork chronograph (spark chronograph) . . . 463 Behaviour of water when freezing or boiling 574 Bebrend, Flow of current in three- phase conductor .... 1005 Behrendsen, Heating on compres- sion and cooling on expan- sion 626 Bela Gati, Baretter set .... 933 Bell, diving 366 - electric 961 - gasometers 212 - of glass, calibrated . . . .211 - of glass on wood base. . . 443 - vibrating 443 - with clockwork 405 Bell, Telephone 1054 Bellows, acoustic .... 425, 426 - hydraulic 336 - model 406 - of rubber 838 — see also vol. I. Belt gear disengaged 328 - gears 328 Benches, Lecture (see Lecture tables) vol. I. Binding elasticity 304 - model 305 - moment 304 - press for glass . . . 559, 564 Bennet, Pile electrometer . . . 840 Bent brass tube 207 - crankshaft 304 — lever 315 - tubing 220 Beranger's Flat balance .... 241 Berard and De la Roche, Specific heat of gases 621 Berghoff, Lines of force theory 963 Bert helot, Calorimeter for deter- mining calorific value of fuels 625 — Alvergniat, Air thermo- meter 582 - Total heat of steam. . . . 622 Berthollet, Mixing (diffusion) of gases . . . - 410 Bertin, Commutator 867 Bertram, Acoustic bellows . . . 426 - Clearing cloudy liquids . . 282 - Inclined plane 268 Page Bertram, Lever apparatus . . . 270 - Parallelogram of forces . . 261 Bertrand, Quadruple quartz plate 566 Berzelius Lamp 209 Bevel wheels ...... 321, 322 Bezold, Continuous progression of tones 439, 445 Bianchi, Vacuum pumps 387 — 389 Bichat, Simplified absolute electro- meter 811 Bichromate of potassium . . . 853 Biconcave lens . . . 557, 560, XV Bicycle ball bearing 302 Biegon, Stationary electric waves 1044 Biernacki, Composition of rota- tions 259 - Gas tap 859 Bifilar suspension, model . . . 886 Billet, Half-lenses 546 Binoculars 540 Biology class rooms, see vol. I. Biot and Arago, Gas prism . . 502 Bi-prism after Fresnel .... 546 Bismuth spiral 956 Black board for dust figures in air plates 442 Blackboard stands see vol. I. Black mirror 554 - mirror for drawing . . 478 — with mount 559 Bladders, burst 403 - of rubber 406 Blast burner , 209 - table see acoustic bellows 425,426 see also vol. I. Bleckrode, Automatic needle co- herer 1051 Blind, electric 806 — for darkening rooms, see vol. I. — spot of the eye 523 Blondlot-Coolidge, Electric waves 1044 - Simplified absolute electro- meter 811 Blood circulation 381 Blotting paper discs 597 Blower, double 425 Blowing tables 425, 426 — see also vol. I. - with siren 423 Blow-pipe 216 Blow-pipe set 1069 Bliimel, Indices of refraction . 486 Board for explaining star and delta connection 1005 — for metal receivers of Kolbe's thermoscope 596 - levelling 205, 206 - suspended, for galvano- meters 879 see also vol. I. — with 3 prismatic blocks . . 275 Boat, combustion 220 Bock, Centre of gravity .... 274 — Eye's model 522 - Model of larynx 444 Body colour and angle of incident light 528 Bohnenberger, Conservation of the plane of rotation .... 292 - Electrometer 809 - Machine 282 - -Fechner, Electrometer . . 840 Boiler for steam engines 634 — 636 — Weinhold's Steam b. 213, 569 - with stand 571 Boiling by friction 285 - flasks 219 - point 606 - determination 580 - stand 203 - tube for Beckmanns appa- ratus 615 Page Boiling tubes for testing thermo- meters 580, 581 - vessel for showing ebullition at higher pressure .... 605 — water 626 Du Bois, Half ring electromagnet 954, 956 — Raymond, Interrupter . . 866 - Slide induction appa- ratus 975 - Rubens, Astatic mirror gal- vanometer 883 - Iron clad galvanometer . . 884 Bologna Flasks 312 Bolometers 648 Bolt and nut 312 Boomerang 409 Borda, Linear expansion . . . 570 Bored carbons and solid cs. . . 513 Borers for cork stoppers . . . 216 Boring and turning chuck, see vol. I. Bose, Exciter for short waves 1041 Bottger, Producing ice by evapo- ration 607 Bottle cells 849 — Mariotte's 380 Bottles for liquids 218 - for reagents or powders . .218 - with glycerine-water mixtures 485 Bottomley, Melting an ice block through by means of a heavy loaded wire 601 Bouguer, Photometer 467 Bourdon, Tube 375, 402 - -barometer 357 Boutigny, Leidenfrost's experi- ment 602 Bow-shaped joint of copper and zinc 839 Box for mercury 215 — for preserving plants, see vol.1. - for rubber part of hydraulic bellows 337 - for storing glass parts of sex- tuple manometer 599 - for tuning forks 438 - telephone 926 - with salts for spectrum ex- periments 517 Boxes and stands for the accesso- ries of Kolbe's thermoscope 598 — and stands for the accesso- ries of Looser's thermoscope 594 — support 206 Boyle's law 365 - apparatus . . . 377 — 379 Boys, Gravitation balance . . . 300 — Lens disc for stroboscopic analyses 526, 837 Brachio-telescope, model . . . 531 Bracket for galvanometer . 879, 883 see also vol. I. Brake ... 1 327 - dynamometers 332 Branly, Coherer tube ... 1051 - Induction currents of higher order 975 — Tube 1041 Brass and wood pendulums . . 266 - balls with different masses 280 - and wood ball on double cord 260 - condenser plates 803 - cube for pressure propagation 335 - disc with 3 magnetic needles 1011 - plates 1033 — plate with steel rod . . . 442 - rod with base and magnetic rod 1011 - rod with ebonite handle . . 797 — rod with 2 balls . . 812 See also the Subject-matter Index in vol. I. 1100 Alphabetical Name and Subject-matter Index. Page Brass sphere 822 - on stem 567 — with fine holes .... 335 - with ring 567 - stands for Melloni's appa- ratus 645 - tube, bent 207 - with rock salt slabs . 646 - wire spiral 414 Brauer, Band brake 252 Braun, Absolute lecture electro- meter 803 - Alternator 1003 - Cathode ray tube . 899, 1073 - Three-phase motor . . . 1003 - Two phase alternating cur- rent motor 1003 - Wireless telegraphy .... 1049 - -Wehnelt, Deflection tube .1024 Bravais, Double plate 565 - Polariscope 556 Breaking model 306 — tests 311 Breath figures, Moser's .... 410 Breathing of human beings . . 408 Breguet, Metallic thermometer . 581 Breitenlohner, Spirit lamp . . . 512 Bresina, Chemical harmonica . . 430 Brewster, Stereoscope 524 Brezina, Coloured plates for inter- ference phenomena . . . 564 Brick with fitting 410 Bridge balance 241 — models 276 - for Noack's experiments . 810 Brix, Calorimeter for determining heat of vaporisation . . . 621 Broad aluminium and copper ring!009 Brodhun-Lummer, Photometer head 469(467) Browne, Boyle's (Mariotte's) law 379 Browning, Pocket spectroscope . 511 - Sparking pillars and spark tubes 514 Bruhns, Rain gauge 656 Brunn. Syphon barometer . . . 373 Bruno, Centrifugal force appa- ratus : ... 277 Briisch, Carbon clamps .... 938 - terminals 996 - Double switch contact rheo- stat see vol. I. - Experimental switchboard see vol. I. Brushes for reagent glasses etc. 220 Buff. Circuit breaking device. . 975 - Demonstration balance . . 239 - Unidirected and opposed cur- rents 968 Buignet, Heat generated by mix- ing liquids 625 Built-up model of lenses. . . . 494 Bulb with phosphorescent cross or mineral 1034 Bunsen, Absorptiometer . . . .411 - Burners 208 - Burner for contraction appa- ratus 568 — — for reversing the sodium line 518 - Burner for spirit 209 — — for universal stand . . 202 - Cell 848 — Demonstration photometer 467 — Kffusiometer for determining vapour density 614 - Eudiometers 220 - Gas indicator 410 - Ice calorimeter 616 — Photometer 407, 472 - Photometer, demonstrating 497 — Reversal of sodium line . . 517 Page Bunsen, Spectrometer 505 - Table of spectra 518 — Universal stand ..... 202 — Voltameter 941 Bunte-Rischbieth's Gas burette 220 Buoyancy and metacentre appa- ratus 342, 345 Buoyancy experiments .... 334 - of air 367 Burette holder 203 Burettes, Mohr's 220, XV Burette stand 203 - with communicating vessel. 346 Burner for Bunsen's univeisal stand 202 - for monochromatic light . 512 Burners for sensitive flames . .418 Burning glass for dark rays . . 644 Bursting bladders 403 Bussy, Heat generated by mixing liquids 625 Busts of Physicists and Chemists, see vol. I. Buth. Horizon 661 Buzzing sound induction appa- ratus . . 930 Cables for electric furnaces . . 939 - qf telegraphs 962 Cage of wire 808 Cagniard de Latour, Siren . . . 420 Cailletet, Liquefaction of gases . 809 Calcium chloride cylinders . . . 219 Calc-spar 560, 1027 - cross, demonstration 552,565 - plate and glass plate with letters .... 563, 565 - preparations . . 565, 566 - rhombohedra 566 Calderon's Double plate .... 566 Calibrated glass bells 211 Calibrating and testing thermo- meters 225 — ballistic galvanometers 976, 1012 - device for gas meters . . . 624 - electrometers 810 Calipers for cover glass .... 538 Caliper with vernier 223 Callendar, Mechanical equivalent of heat 629 Calorifere 419 Calorific value of fuels . 622 — 625 - of hydrogen 622 Calorimeters, electric . . 936, 937 - for determining specific (ab- sorbed) heat . . . 616 — 622 - for determining the heat of combustion 623 — 625 Calorimeter thermometer 577, 623, 624 — vessel 618 Caloriscope 936 Cam disc 318 Camera lucida 530 — obscura 530 - demonstrated . 483, 496 Cameras photographic . 520 — 522 Cam motion 318 - shaped cogs with excentric axes 321 Campbell-Stokes, Sunshine re- corder 652 Cunal ray tube 1022 Candle holder . . . 474, 812, 813 - Jablochkoff's 996 Candles, standard 472 Cannon for demonstrating the action of a couple of forces 262 Page Can of sheet 102!) Capacity measuring !K!."> — meter 813 - of electrometer determined 811 Cap for school-spectroscope . . 510 - of platinum with Bunsen burner 643, 645 Capillarity 362 — 364 Capillary attraction and repulsion 360 - dropper for mercury . . .215 - electrometer 946 - galvanoscope !I4(> - hygrometer 653 — tubes 334 Capstan 313, 330 Capsule, double walled . . . .612 - for bolometer (il it Capsules 939, XV Carbon capsules 939, XV — clamps 938 - crucible 217, 938 - dish 21S - disulphide prism 501 - filament lamp 996 — for electric furnace . 938, 939 - lines, photograph 550 - oxysulphide tube 613 - plates, spare 852 - resistance see vol. I. ... — rods for arc lamps 201, 513, 938, 939, 996 see also vol. I. - terminals 865 — after Briisch 996 Carbonic acid generator .... 609 — — tubes 613 Cardan's coupling . . . 316, 317 Cardboard disc 1025 — sheets with magnetic strips and bars 788 Card board with metal strips . 986 Carl, Tangent electrometer . . 801 Carre, Freezing apparatus . . . 405 — Ice machines 600 - Refrigerator 608 ( 'arriage and spring dynamometer 258 - with movable rollers . . . 2.~>1 Carrier for suspending rules . . 222 Carrying case for chronographs 249 - cases for induction coils . 982 - case for electroscope . . 1029 - for model theodolites . 532 - for photometer .... 466 - power of a magnet measured 788 Cartesian diver . . . 334, 382, 383 Carton with strips of metals. glass etc K'73 Cartridge for Parr calorimeter . 623 Cascade battery 832, s:t:i - electric 406 Case for balance 238 - for calorimeter 624 - for electrometers Io21> - for gas meter l>24 - for quadrant electrometers S42 - with phosphorescent sub- stances ">!!'. "''Jit - with quartz fibres .... 843 - with razor etc. for micros- copy 538 Catacautery 477 Cathetometert -'24 Cathode ray tube 899, 1024. 1073 Catskin. rubber 797 Caustic line 476. 477 soda 849 Cavendish, Attraction of mass . :!OO — Condenser 1O72 Cedarwood-oil-tubc 494 ( 'eilin.i: arrangement lor transport- ing purposes see vol. I. Celestial globe r,i;i See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1101 Page Cello bow 440 Cells, electric, for demonstrations 844—848 — for ordinary use . 848 — 853 - st.-nulard 844, 845 - with potassium or sodium 1026 < Ylluloid top for Bunsen cells . 848 < 'entering device for goniometer 482 Central force electromagnet . . 278 - pencils of rays 488 Centre of gravity . . 267, 274, 275 - of gravity figures 274 Centrifugal apparatus . . 277, 280 - balance .......... 281 - force 276 — 282 - governor, equilibrium con- ditions 316 - mercury interrupter .... 983 - pendulum 258 - psychrometer 655 - pump 385 - pump and blower .... 282 - railway 276 Chain for connecting electric ma- chines and apparatus. . . 824 - transmission 328 Chalcolite plate 517 <'hiinge device for telescope . . 543 - gears 326 - of state 600—615 - of state (experiments with the thermoscope) 592 Channel balance 342 Chappuis, Gas thermometer . . 582 Chancing devices for accumulators 857—861 - switchboard 859 Charts, meteorological .... 660 Chart of stars 662 Chassis for locomotive .... 637 Chatlock, Electroscope 800 Checking the penetrative power of X-rays 986 Chemical balances. . . . 231 — 244 - experiments with Looser's thermoscope 593 - harmonica 430 - laboratory see vol. I. - spectrum apparatus .... 508 - store cupboards see vol. I. - supplies, estimates 1085 — 1093 Chemicals .... 1086, 1090, 1091 see also vol. I. Chcmico-technical balances 234, 235, 623 Chemistry Class Rooms, see vol. I. - Lecture Tables, see vol. I Chime 825 Chimney cowls, sucking action 408 - for Bunsen burner .... 208 Chladni's Figures 442 Chlorine tube 613 Chopper for ice 214 Chord, fall through it 258 - siren 421 Christiani, Wave machine . . . 416 Christiansen, Mechanical equiva- lent of heat 629 Chromatic aberration . . 488, 495 Chronographic tuning fork . . 455 Chronographs 248, 249 Chronometers 249 Chronoscope 244 - (Ilipp's) 248 Church bells tested 438 Cinematograph 526 see also vol. I. Cinematographic photos .... 899 Circle dividing engine 228 - Jamin's for measurement of reflection, refraction and po- larisation ... . 499 Page Circuit-breaking device .... 975 Circular double refraction . . . 563 - groove with circular slot . 312 - motion diagraph 260 - photographed grating . . . 549 - stout copper wires . . . 1034 - vernier model . . . 228, 229 - wave motion .... 415, 416 Circulating syphon 381 Circulation of the blood . . .381 - of water 573, 574 Clack valve, model 408 Clamp for exciting tuning forks 440 - universal 204 - (Westien's) 202 Clamping stand 368 Clarinet mouthpiece 427 Clark, Standard cell . . . 844, 845 Classen, Interference apparatus 545, XV Class room equipments see vol. I. Claw coupling 326 Clay cylinders for pyrometers . 587 Clearing cloudy liquids . 277, 282 Clemens, Coupling 317 Clement and Desormes, Specific heat of gases 621 - Suction action . . . 408 Clinical thermometer 578 Clip for branches 866 Clipping device for coherer 1052, 1053 Clock movements 333 - universal 662 - with electric contact . . . 246 - with 10 seconds signal . . 245 Closed iron ring with coils . .991 - mercurial pressure gauge. . 369 Closing discs for electrometer 1029 Clutch engager with screw . . 326 Coating for rubber slab .... 822 Cocks for tubing 207 Coddington glass ....... 530 Coefficient of expansion 569—572, 575, 576 of gases 377 - of linear expansion . 570, 571 - of pressure increase .... 576 Cogs, cam shaped, with excentric axes 321 Coherer 1051, 1052, 1053 - for short waves . . . . 1041 - tester 1049 Cohesion and adhesion . 360, 361 - and adhesion tube .... 405 - plates 360 - syphon 360 Coil for generating a homogeneous magnetic field 1012 - for showing induction by earth-field 972 Coils for galvanometer .... 883 - for iron clad galvanometer. 884 - on stand 899 - with handles 950 Coin-reprints 948 Cold thermometer 610 - water float 345 Colladon, Apparatus for total re- flection 494 - Eddy apparatus 659 Collapsible apparatus for astrono- mical geography 662 Collection for fluorescence ex- periments 518, 519 — of accessories for Kolbe's thermoscope . . . 595 — 598 - of accessories for Looser's thermoscope . . . 589—594 - of apparatus for magnetism, frictional contact and ther- moelectricity ...... 787 Page Collection of apparatus for re- flection and refraction . . 493 - of apparatus for the laws of mechanics 265 - of auxiliary apparatus for the influence machine .... 825 - of chemical supplies 1085 — 1093 - of microscopical prepara- tions 538 — of physical apparatus 1075 — 1085 Collections of physical apparatus for projection . . 1094 — 1096 - of preparations for spectrum experiments 517 - of radioactive preparations 1027 Collimator lens 560 - tube with micrometer gap . 513 Collodion balloons 368 Colour bottles for microscopy . 539 - -contrast, successive and simultaneous .... 526, 527 — discs 284, 504, 529 - dissipation 479 - filters (gelatine slabs) . . . 528 - formation by polarisation . 562 — glasses (Newton's rings) . . 544 - of thin plates . . . 543, 544 - projection in colours, see vo!. I. - ring apparatus 544 - rings, Nobili's 947 — synthesis 529 - thermoscope (Rebenstorff's) 600 - top 529 Coloured convex surface . . . 284 - flames 513 — 515 — glass plates 516 - interference rings 544 - leaves, thermoscopic . . . . 642 - plates 516, 517 - after Brezina 564 - shadows 527 - wool in portfolio 529 Column of glass plates . . 554, 559 Columns of air, vibrating . . . 426 Combining rotations 292 Combustion boat 220 - heat calorimeter . . .622 — 625 - tubes 220 Communicating tubes . . . 334, 342 - water vessels 814 Commutator 866—868 - double 935 - for transforming current .1004 - multiple 883 Comparative explanation of wire- less and ordinary telegraphy 1047 Comparators 225 Comparing resistance of different materials 911 - two tones of pipes .... 462 Comparison glow lamps . 470, 471 - of superficial colours . . . 544 — resistances for Wheatstone bridge . . . •. 918 Compass 792 - needle 786 Compensated water dilatometers 572 Compensating pendulum 245, 294 Compensator (Babinet's) .... 556 - for resistance thermometer 587 Complementary colours produced 528 - series of tuning forks . . . 445 Complete exciter for short waves 1041 - installation for interference and diffraction experiments 560 Composition of impact forces . 258 - of rotations 259 Compound microscope, model . 531 - motions 258 — 260 - parallel vibrations 453 See also the Subject-matter Index in vol. I. 1102 Alphabetical Name and Subject-matter Index. Page Compressed air 610 Compressibility of gases . 359, 603 - of liquids 358, 359 Compression hygrometer . . . 654 - measured 310 - of gases and temperature change 626 - pump 407 Compressive and tensive strain 269 Compressor pumps 395 Concave and convex lenses 494 — 496 — and convex mirror .... 477 - mirrors 596, 643 — mirror with selenium cell 1059 Concentration cells 947 Concentric nodal lines .... 442 Condensation of gases and vapours 592 Condenser 811, 833, 834, 900, 933—935 — after Cavendish, 1072 - bed (Apostoli's) see special list — electrolytic 864 - for electroscope 800 - for Paalzow optical bench 557, 560 - (staged) for singing arc lamp 1058 - lens for photophonic appa- ratus 1059 - plates 803, 810 - spherical 811 - standard . . . 813 Condensing and dispersing lenses, explanation 488 - lens 494 — 496 Conditions of sale IV. - of heat see cooling action 406 Conducting resistance and tempe- rature 912, 913 - wires 810 Conduction of heat by solids, demonstrated with Kolbe's sextuple manometer . . . 599 - of heat in mica 1020 - of heat (with Looser's ther- moscope) 590 - of liquids and gases (experi- ments with Kolbe's ther- moscope) 597 - thermal 638 — 648 Conductivity of electrolytes 929 — 933 - of heat see thermal con- duction 638 — 648 - vessel 930, 931 Conductor after Kolbe .... 913 — ball 805 - of current 950 - rails on lecture tables, see vol. I. - with sharp point 807 ( 'oncluctors, which can be leng- thened 805 . Com- and its perspective image 529 — of crystal glass 503 - pulley drive 328 Cones (Seger's) for pyro metric measurements 587 - with stand for equilibrium demonstrations 274 Cone transmission by belt . . . 328 Congruent elliptical toothed wheels 321 Conical crank rectangle .... 316 - mirror 476 - pendulum 293 — resonators 450 - thrust crank chain .... 316 - tube for showing the brha- viour of wetting and not- wetting liquids 363 — valve 408 Conic refraction 564 Connecting and disconnecting de- vices 326, 327 Page Conneeting chain 824 — flexibles 935 — leads 822, 930 - piece with platinum foil . . 847 — rod with guides for stroke doubling 325 — switchboard for galvano- meters 888 - syphon 381 — wires 810 Conservation of the centre of gravity 251 - of the plane of oscillation 283 Constant-action mercury vacuum pump 398 - battery 846 — cell 846 - of capillarity 362 Constantan resistances for experi- ments with Kolbe's thermos- cope 598 Constituents of air balloon appa- ratus 367, 368 Constriction, electric 836 Contact device for Foucault's pen- dulum 298 - lamp after Reynier .... 996 — rheostat 915 - ring for turbine interrupter 984 - thermometer 580 Containing box for tuning forks 438 Contents VII. Continuity, laws .... 251, 289 Continuous progression of tones 439, 445 - vapour spectra 512 Contraction apparatus .... 568 — of an extended rubber tube by heat 571 — of a vibrating bar 433 — of bodies 567 — of gases and temperature change 626 - of liquids 361 Contrast back ground and mirror device see vol. I. Contrasted colours as coloured shadows 527 Contrast photometer 467 Convection of heat in water . . 573 — of water 573 Converging polarised light passing through a calc spar plate 562 Convex and concave gypsum plates 564 - and concave mirror . 477, 478 - lens 473 Coolers 210 Cooler stand 203 Coolidge-Blondlot, Electric waves 1044 Cooling action of gases . . 406, 642 - of gas by pressure diminution 591 vessel for explosion ball . . 600 - for Hofmann's apparatus 614 Copies of genuine Rowland grating 549 - of precious stones. . 1066, 1067 Copper and zinc plates .... 839 - and zinc rods in cork mount (access, to Kolbe's thermos- cope) 598 - condenser plates 803 - disc and rotating magnet . 287 - rotating ....... 952 — dish with wire triangle . . 602 - -mercury iodide 639 • -plating apparatus .... 948 - rod with 6 receivers . . . 599 - screen, blackened 645 stirrup 1033 - sulphate 853 \ollameter 943 — wire 206, 207 Page Copper wire fine bare 814 - zinc cell 845 - standard 844 Cord drive 32K - gear for rotating colour discs 279, 504 Cords for fall experiments . . . 253 — of indiarubber 414 Core transformer . . . 1007, 1008 Cork borers 216 - press 216 Cornet mouthpiece 427 Corrigenda XV., see also vol. I., p. II. Cosine theory of mechanics . . 260 Cosmology ....... 660 — 662 Coulomb, Brass ball on insulating stand 807 - Magnetic magazine .... 786 — Law 794, 795, 809 - for electricity . 804, 805 — Torsion balance 794 - Tribometer .... 301, 302 Coulombmeter 943 Counteraction apparatus 290, 291 Counter-motion anti-parallel cranks 314 Counter of speed 999 - trade winds 658 Counting mechanism . . 324, 326 — for whirling tables . . 280 Couple of forces 262 Coupling with friction cone . . 326 Couplings 315—317 - connecting and disconnecting devices 326, 327 Covered pipes 426, 428 Cover glass calipers 538 — glasses 538 Cow hide back 521 Cranes 330. 331 Crank and slot 315 - gears 314. 315 — rectangle :>!»> — shaft 314 Crankshaft, bent 3<>4 - with moving parts .... :tn."> Critical periodicity of a force . 297 — pressure see iodine tubes . 60] - temperature phenomena . . solving tension of salts . . 364 Distillation tables see vol. I. Distilling apparatus for merrury 399 Distributing apparatus . 805, 806 Distribution, electric 811 - of magnetism in a bar magnet 788 - of pressure in tubes . . . 33(i Diver, Cartesian .... 382, 383 Divided circle and index for Nicol prisms 559 Dividing engines .... 227, 228 ruler 222 Diving bell 366 Page Divisibility of fuchsin 250 Dobereiner, Hygrometer .... 652 — Tinder box 410 Dobrovolski, Ammeter 905 Dolezalek and Kriiger, Current flowing through a liquid . 848 - Quadrant electrometer . . 843 Dolger, Tuning fork exciter clamp 440 Donny, Water hammer .... 606 Doppler's Principle 283 Doppler, Theorem 935 Double absorption box . . . .516 - and differential thermoscope after Kolbe 595 — barrel vacuum pumps 389. 392—394 - bridge, Thomson's .... 927 — bulb for gas expansion . . 250 - calorimeter 618 — chamber air thermometer . 582 — commutator 935 - conductor with plug contact for experiments with Kol- be's thermoscope 598 — cone on inclined stand . . 274 - coupling, Cardan's .... 317 - cycloidal railway 267 - electric pendulum . . . .811 — — whirl 825 - excentric with reverse motion 3 1 8 — fan 405 - gap . . 512 — glass vessels for comparison of electric resistance . . . 599 — grating 548 - gun 252 - hooks for suspending rods 797 — hook weights . . 260, 273, XV - inlet channel slide valve . 633 — key 868 - for Wheatstone bridge. 919 — needle 968 - oscillograph 900 - pachy trope 1003 — pendulum 297 - after Airy 451 — — electrodynamic .... 969 — magnetic 787 - pin gearing 319 - plate after Bravais .... 565 — plates, double refracting . 566 - prism on stand 500 — radiometer 1021 - refracting prisms 560 - refraction . 416, 556, 562 — 566 - regulating cock 825 - roller 827 — rotation influence machines 819—821 - screen 646 — siren 422, 423 - socket, universal 202 - sphere on stand 410 — spherical condenser . . . .811 — strand for resistance thermo- meter 587 - thermoscope (Looser's) . . 589 — trough after Hallnaclis . . 502 - universal coupling 317 — vessels of glass 597 - walled capsule (112 Dove, Chord siren 421 - Polarisation polyoscope . . 563 Draining and drying apparatus. L'SL' Draught apparatus 408 - boxes, draught pipes, see vol. I. Drawings for showing the blind spot 523 Drawn brass tube ( Hebenstorff'.s) 41!), 569 Page Drebbel, Thermoscope 568 Drenteln. Resonance apparatus 443 — Sound interference tube . . 4H-J Dressing machine 354 Driving device Mini Drop of potential 810 Dropping apparatus (surface ten- sion) 302 - pipette 362 — vessel for mercury . . . . 215 Drude, Dielectric constant of li- quids 1045 - Tesla transformer with Ley- den jar 1(I4."> - Wavemeter .... 1044, 1045 Drum armature 991 - pyrometer 569 — rheostat 916 — stroboscopic .... 417, 525 - Tyndall's 486 Drumstick for striking tuning forks 439, 440 Dry cells 850, 935 - cell battery box 886 Drying and draining apparatus. 282 - apparatus for the air pump 401 - cylinders 219 — device for paper tube . . . 797 - tubes 219 Dry-plates 1074 Du Bois, see letter B Duboscq, Polarisation apparatus 551 - Projection polarisation appa- ratus .~>.~>2 Dubrowsky, Influence machine 813, 817 - -Loossr, Aspirator action . . 598 Ducos du Hauron, Anaglyphon (plastoscope) '<-'.> Ducrue, Projection parabola . . 264 Duhamel, Vibrograph 456 Dulong, Thermal radiation appa- ratus 648 Dulong and Petit, Calorimeter . 62o - Linear expansion . 570 - Mercury expansion 574 Dulong and Petit 's Law . . . .617 Dumas, G-as and vapour densities 613 Duplex barometer 371, 372 - pressure gauge 369 - vacuum pumps .... 392 — 394 Duration of luminous impression 525 Diirr, Boiler 636 Dust figure apparatus 434, 442, 44(1 - figures, Chladni's 44 -2 - proof lock-up cupboards for influence machines . . . s-J I Duter, electric constriction . . situ Dutrochet, Endosmometer . . . lid I Dvorak, Mechanical effects of sound 463. Id I Dynameter after Ramsden . . .VI it Dynamic balance -,~>2 Dynamics and statics . . 265 — 411 Dynamoelectric induction in dy- namos 987— '.ml - principle -'ss Dynamometer -.">- - models (friction brakes) . . :>.'!- Dynamometers for cloth and yarns see special list. - (spring balances) 310 Dynamometrical measuring in- struments 910, 911 Dynamos, direct current, for ma- chine drive, see vol. I. explanatory models . .987 — 991 — for generating current 992 — 9!t4 Dynaphor. Heil's (The apparatus cannot be furnished). 861. X \ Dynmeter 7SI5. 1072 See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1105 Page E Ear. model 444 Earth induction 288 - inductor 972 - minimum thermometer . . 650 - thermometer 650 Earthenware basins, see vol. I. Ebb and flow 661 Ebbinghaus, Interval apparatus and tonometer 448 Ebert, Phosphorescent lamp . . 1034 Ebert and Wiedemann, Calori- meter 618 Ebonite discs 810.1025 — for gramophones . . . 461 - electro phorus 814 - plate 813 - plates for influence machines 824 - plate for the screening effect 812 - rod 814, 1029 - flint glass rod etc. 797, 798 — with amalgamated leather rubber 812 - with brass terminals . 866 - table, insulating 809 Ebullition 605 - see also Boiling phenomena - under low pressure .... 606 Echelon grating after Michelson 507 Eddy apparatus 658, 659 Eddy currents generated . . . 977 Edelmann. Cylindrical quadrant electrometer 843 - Pall apparatus .... 255, 256 - Foucault's pendulum . . . 298 - Physical work stand . . .201 Eder and Valenta, Continuous vapour spectra 512 Edison Accumulators 857 - Effect 1026 - Phonograph 460, 461 Effect, Zeeman's 507 Efficiency measurement .... 252 Efflux method for determining vapour densities 614 Effiisiometer 411, 614 Egg, electric 406, 830 - of aluminium 1004 - -shaped conductor .... 806 Egyed, Mechanical model of elec- trolysis 945 Eichhorn, Universal Gasometer. 212 Einthoven, Electromagnet string galvanometer 891 Eisenlohr. Glass balloon with gly- cerine-soap solution . . . 543 - Glass globe for Newton's rings 285 - Plane of oscillation .... 283 Elastic impact 302 - limit 311 - line 306 Elastics, lined with copper wire 825 Elasticity 302 — 312 - of air 366 Elder pith ball 1025 Electric action of points . . . 827 - arc 406 - assay furnace . . . .938—940 - balance 804 - bell 961 - for wireless telegraphy apparatus 1048 - in receiver 405 - blind 806 - cascade 406 - charge of a body 807 - conduction in gases .... 1014 - conductivity, shown with Kolbe's sextuple mano- meter 599 Page Electric constriction 836 - contact thermometer . 580, 581 - dancing balls 826 - dial 246 — egg 406, 830 - endosmose 945 - equivalent of heat . . 936, 937 — experiments with Kolbe's thermoscope 598 - with Looser's thermo- scope 593 - glow 'lamp . . . 452, 995, 996 - harmonica 430 - horizontal pendulum . . . 798 - incandescent lamp . . 843, 878 - laboratory furnaces .... 940 — lighting . 995, 996 - lines of force 813 - machines 815 — 822 - measuring instruments. 871 — 911 - melting furnaces . . .938 — 940 - mortar 826 - motor for Parr calorimeter 623 - for radiophone .... 649 - for siren 423 - to be used as whirling table 280 - motors 997, 1000 - for darkening devices, see vol. I. - needle 811 - oscillations 1030—1053 - pendulum . . . 798, 805, 811 — pistol 825 - potential 809, 810 - power rays 1039 - pyrometer 584 - radiometer 1020, 1021 - railway (model) 998 - resistance comparison with Kolbe's manometer . . . 599 - thermometers .... 585 — standard clock 247 — thermometer 829 - thunder cloud 827 - tourbillion 828 - water baths 210 - waves, stationaiy . . 1043, 1044 - whirl 825 Electricity at the ends of an elongated conductor . . . 806 - produced by temperature changes or pressure . . . 838 - provision of, see vol. I. - static 797 — 838 - voltaic 839—949 Electro-chemistry 940 — 949 Electrochemistry: laboratory tables see vol. I. Electrodeless tube. . . . 1025, 1034 Electrodes, electrolytic .... 947 - for electrolytic rectifier . . 864 Electrodynamic actions . .966 — 971 Electro -dynamic pendulum . . 969 - -dynamics 949- — 971 Electrolysis of water . . .940 — 942 Electrolyte resistance . . .928 — 933 Electrolytes for cells 853 - e. m. f. at their limits. . 847 Electrolytic apparatus . . 943, 944 - condenser 864 - decompositions and crystalli- sations 944 - demonstration apparatus. . 945 - forge 946 - interrupter 928, 982 - rectifiers 863—865 - resistances measured . . . 886 - salt for rectifiers 864 - stand 947 Electromagnet . . . 950 — 958, 973 - for Beckmann's apparatus 615 Page Electromagnet for explaining the dynamo 988 — string galvanometer .891, 892 — with foot terminals. . . .1012 Electromagnetic action on flexible conductors .... 971 Electro-magnetic current measure- ments 871—911 Electromagnetic induction, quan- titative measurements . . 1012 - instruments 906 - motor 957, 958 - for Geissler tubes 958, 1017 - release for fall machines . -. 254 - soft iron demonstration in- struments 904 Electromagnetic telegraphy 958 — 962 Electromagnetic units, introduc- tion 1010—1013 Electromagnetism . . . .949 — 971 Electrometer 801—804, 809, 810, 812, 841—844 - absolute 803, 804 - balance 844 - capacity 811 - capillary 946 - for atmospheric electricity 814 - for investigating radioactive substances 1028 — Kolbe's 809 - with pile 840 - quadrant electrometer 828, 841—843 Electromotorical force at the li- mits of 2 electrolytes . . 847 Electron theory .... 1025, 1026 Electrophorus 814, 815 Electro-plating apparatus . . . 948 Electroscopes 799 — 802, 808, 811, 812, 1025, 1028, 1029 - small 809 Electroscopic powder ..... 1025 Electrostatic apparatus as sug- gested by B. Kolbe .811—814 - demonstration voltmeter . 905 - measurements, Noack's . . 810 - motor 826, 827 Electrothermic apparatus . . . 1064 Elementary electrostatic measure- ments 810 Elements of machines .... 312 Elevation-angle 263 Elliptical propagation of heat . 639 - toothed wheels 321 — wave motion 415, 416 Elongation of paladium on ab- sorbing hydrogen . . . . 853 - of a wire by current heat 937 Elster and Geitel, Electrometer 801 - Electroscope . . . 1029 - High tension trans- former 1031, 1038 - Potassium cell . . 1026 — — Quadrant electro- meter 843 - Vacuum deflection tube 1034 - Zamboni pile . . . 809 Emery disc for hardness tests . 281 Emission of heat 644 — 648 - of heat (experiments with Kolbe's thermoscope) . . 596 Emsmann, Universal wheel appa- ratus 320 Emulation of the visual fields . 524 Enamelled kettle 214 Enclosed vacuum pumps . 395, 396 Endosmometer . . . 364, 365, 410 Endosmose, electric 945 - of gases 410 Energy, total and thermal . . 937 See also the Subject-matter Index in vol. I. 70 1106 Alphabetical Name and Subject-matter Index. Page Engaging and disengaging ar rangements 326, 327 Engelmeyer, Kinegrapb . . 259, XV Engines, gas, see vol. I. - internal combustion, see vol. I. - with dynamos, see vol. I. Engler and Sieveking. Electro- scope 1029 - Fontactoscope .... 1029 Enlarging apparatus, photogra- phic, see vol. I. Epicycloid formation 318 Epicycloidal gear 324 — — • system 319 — with bevil wheels . . 326 Epidiascope see vol. I. Equal arm lever 265, 269 Equal limb rotating slot and crank 315 — -limb syphon 381 - weight figures 360 Equalisation of pressure .... 336 — of rotating masses .... 262 Equality of inducing and induced electricity 808 — photometers 465 — 468 Equilateral crank gear .... 314 - rock-salt prism 596 Equilibrium apparatus. . .273 — 276 - conditions 289, 270 i — figures 274 - of gases 365 — 385 - of liquids 334 — 358 - of vapour tsnsions .... 695 Equinoctial precession . . . .661 Equipment of class rooms and laboratories see vol. I. - of workshop, see vol. I. Equivalent of heat, electric. 936, 937 - of heat, mechanical 285, 286, 627 Erdmanu. Freezing water in li- quid air 612 Ergin motors see vol. I. Erlemann, Sliding and plug rheo- stat 914 Errata XV — see also vol. I. Escapement pendulum. . . 258, 297 Estimates as to equipments of class rooms and laboratories see vol. I. - as to Physics and Chemistry equipments, see vol. I. - as to physical and chemical apparatus 1075—1093 - tor Megadiascopes, see vol. I. - for projection outfits 1094 — 1096 - of cost for chemical supplies 1085—1093 - of cost for physical appa- ratus 1075— 1HS5 lltliri igniting 813, 826 Eudiometers 220 - and glass cup 941 Evacuated bulbs 1034 - double vessel 597 Evaporation and thermal con- sumption 597 — apparatus 210 - ice 608 - of ether »o.-, Excentrie 318 - drive with guides .... 317 slot 317 Exciter clamp (or tuning forks 440 - for short waves lot I - for stationary wire waves . 1044 - solenoid . .' lo:!7 Exner, Electrometer 801 Expansibility of saturated steam 604 Expansion and elasticity of wires 303 - and jolting 311 - anomaly of water .... 573 Page Expansion coefficient of air . . 576 — coefficient of gases 377, 574, 575 — flasks 572 — of a vibrating bar .... 433 — of gases 250, 410 — • of gases and temperature change 626 — of liquids and gases 567, 568, 577, 594 — of mercury 574 — • of solids 567' — of water, absolute .... 594 — • thermal (with Looser's ther- moscope) 589 Experimental barometer . . . 372 — switchboards see vol. I. Explosion ball 600 Extending thermometers . . . 585 Extension, measured . . . . .310 - of wires 303, 304 External circuit, heating. . . . 847 Extra carbons 938, 939 — - -current 976 - discs for stroboscope . . . 526 — • globe for Mang's apparatus 662 — jars 1038 - plates of solar spectrum . 550 — resonance-coil 1038 Eye and phenomena of vision 522—529 -fatigue 526, 527 — human, explaining .... 496 . -model 522, 523 Eyepiece, astronomical, for tele- scopes 543 Fabry and Perot, Interference plate 507 Factory of Max Kohl A G. . V Fahrenheit, Hydrometer .... 346 Fall apparatus 253 — 258 — cords 253 - cylinder 404, 405 — machines 253 — 256 - pipes 253 — pistol 263 — through the chord . . . .258 — trough for shutting a current- circuit 248 - tube 404, 405 Falling of a liquid in vacuo . 606 - slide for cinematographic photos 899 Fan 405 Fanlight darkeners see vol. I. Faraday, Freezing mercury. . . 607 - Beaker .so; - Glass block 955, 956 - Induction current when an electromagnet is magne- tized 973 - Method for graduating an electrometer 810 - Muslin net 808 — Rotation of a conductor 970, 971 — Second law !i44 Farcot, Parabolic governor . . 637 - Slide valve cylinder . . . 632 Fatigue, optical 526 Favre and Silbermann, Oalorimein for determining the heat of combustion (>2:i — — Heating of the air on compressing and cooling on expansion 626 - Mercury calorimeter (il'.l Fechner-Hohnenberger, Pile elec- trometer ... . S4o Page Felt, amalgamated 797 Female scale for dividing engine 228 Ferraris, Crossed cods . . . . . 1003 Fessel, Top 2! 12 Fessel and Pliicker, causing an induction current .... iiVii — — — Wave machine 415, 416 Feussner, Accumulator battery . s.">7 Fibres of quartz 843, 883 Fiddle bow 440 Field and opera glasses .... ,540 — goniometer 229 — intensity, measuring . 955, 956 — magnetic ...... 96-' — 965 Figures for the centre of gravity 274 - of gypsum 5r>5 - LiSSHJOUS 451 — 455 Filament of glow lamp .... 523 Filings of iron 789 Fillet with two lens mounts . . 498 Filling pipette for barometer tubes 602 Film pack slide 521 Films for cinematographs . . . 526 — see also vol. I. Filter paper 220 - stand 203 Filtration apparatus for mercury 399 Final velocity of a body . . . 258 Finder for telescope 543 Fins bare copper \\ire .... 814 - motion for telescopes . . . 543 Finkener's P.urner 209 Fire engine 385 — • syringe 626 Fhmament views, stereoscopic . .">•_' 4 Fischer, Fork electroscope . . .801 — Water pyrometer 587 Fischinger, Dynamometer . . . 252 Fixed nut with rotary screw spindle . . . 313 — screw spindle with rotary progressive screw-nut . . 313 — sounders 809 — wire frame 988 Fixing device for suspended board 883 Flame collector 801, 814 — images 284 - pipe 428 Flames, sinning 430 Flasks . ?19 — for washing gas 220 — with absorbent liquids. . . 516 Flat balances 'J41 — electrodes 947 — induction coil 955. !>.~>i> - ring, Schuckert's 990 — selenium cell loin Flattening a sphere . . . . 281. 360 Fleeming, Standard cell . . . . Ml Fleischer, Cell 850 Fleming-Crookes, Cross shadow tube 1019 Flexible cord 1054 — leads 206 — lighting cable, see vol. I. — wire netting 811 Flicker photometer head. . . . -Itl'.i Flint glass prisms 4!»9, 5lil> - rod, ebonite rod etc. 797, T'.'s Float apparatus 344 - inverted 880 Flo; ler for burettes -'-'<> Floating current '.His Flow and ebb 661 - of current in three-phase conductor 1005 - velocity 345. 355 Fluid Compass 792 Fluorescein screen 1073 Fluorescence 518. 519 s| truin 51!) See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1107 Page Fluorescent liquids 519 - portfolio 519 — screens 986 Fluorspar cube 518,1027 Flushing tables, see vol. I. l-'ly- wheel and toothed gearing . 313 Focus-inn stage ror micro-photo- graphic apparatus .... 539 Foghorn 429 Folding camera 520, 521 — csll 847 - magnifier 530 Fontu'-ioscope 1029 Foot or stand clamp 799, 866, 1010 Force action of a weight . . . 251 - lines 788, 830 - electric 813 - pump 383 — 385 - pumps see also vol. I. — table 262 Force;! oscillations 297 Forceps for shunting 916 - for smoothing the aluminium leaves 814 Forces and Motion . . . .251 — 264 - couple of . 262 — impact, composition . . . 258 - parallelogram of . . .260 — 262 Forge, electrolytic 946 Fork electroscope 801 - -shaped tube for interference 462 Formation of the cycloid, epicy- cloid, hypocycloid, involute 318 - of the screw line 273 Forming ice by evaporation . . 405 Fortin, ( istern barometer 372, 374, 375 Foster, Heating effect of current 936 Foucault-currents 288 - Pendulum 283, 298 - Photometer 468 - Prisms 565 - Rotating copper disc. . . . 952 Fountain, Heron's 382 - intermitteat 382 Fourneyron, Turbine 357 Fourth aggregate condition . .1018 Fox -tail rubber 797 Fractional gram weights . . . 243 Frahm, Resonance top .... 2^9 Frame of oak 260, 265 Frames with pendulums . 293, 294 Frankel, Astigmatic test card . 523 Frankland, Reversal of sodium line 518 Franklin, Electrode holder . . 822 - Press with portrait pattern 826 Franklin's Law 799 - Plate ' . . . 835 — Rose 822 Franklinization 822 Franz, Thermal conduction in 'rods 633 Fraunhofer, Line-demonstration 5.">( i - Refractive indices .... 479 - Screw micrometer .... 225 Free axes 282 - fall 256, 257 Fice/.er, american ...... 214 Fie. /.ing air and oxygen. . 610, 612 - apparatus 405 - mercury 607 - point determination . . . 580 - thermometer 600 - water 574, 600 - water in liquid air .... 612 Frequency of tuning forks 455 — 457 Fresenius' 1 >essiccators .... 219 - Spray flask • . . 220 Fresnel, Explanation of the rota tion of the plane of polari- sation 259 (551) Page Fresnel, Glass press .... 559, 564 — Interference prism (bi-prism) 546 — Mirror experiment 544, 545, 561 — Ocular micrometer .... 545 - Parallelepiped 556 — Prism for showing circular double refraction 563 Freyer, Mechanically movable plates for illustrating dyna- mos and motors 990 Frick, Dalton's law apparatus . 603 - Inclined plane 267 - Parallelogram of forces . .261 - Percussion apparatus . . . 303 - Reversing pendulum . . . 295 - Screw apparatus 273 - Stable equilibrium .... 274 - Wedge apparatus 272 Frictional contact electricity . . 787 - electric machines . . . 815, 816 Friction brake 332 — cone coupling 326 — heat 285, 626 - internal, of liquids .... 364 - of journals' 302 — sliding 268, 301, 302 — wheels 327 Frieirichs and Greiner, Mercury vacuum pump 397 Frog's leg experiment 839 Froment, Electromagnetic motor 958 Fuchs, Counteraction apparatus 291 - Pendulum race 281 Fuess, Heliostat, see vol. I. Fulgurator (spark tube) .... 514 Fulminating flask 828 - plate 835 — slab 828 - tube 828 Fundamental electric experiments 798 - experiments, voltaic . 839 — 842 - laws of magnetism .... 787 - resistance experiments . . 911 - theories of optics 496 Funnel, magic 380 — tubes 219 Funnels 219 Furnaces, electric 938 — 940 Fuses, heavy current 938 6 Galilei, Air thermometer (ther- moscope) 567, 581 - escapement pendulum 258, 297 - Inclined plane 257 - telescope 531 Gall, Chain transmission . . . 328 Gallows, portable 206 Galton's Whistle 445 Galvanic cells 844 — 853 - demonstration cells . . 845 — 848 - sources of current . . . 839 — 865 Galvani's Experiment 839 Galvanometer, different types871 — 897 - (recording) for resistance thermometer 586 - lamp, see vol. I. — scales 879, 880 - scales see also vol. I. - shunts 893 - suspension • 884 — see also vol. I. Galvanometers for thermocouples (pyrometers) 585 - tangent galvanometers 871 — 873 Galvanoscope, capillary .... 946 Galvanoscopes 875 Gap, adjustable 512, 545, 546, 560 — with micrometer :screw . . 648 • ' i }' •' Page Garbasso, Model for explaining the Hertzian resonance pheno- mena 1045 — Parabolic concave mirrors . 1042 Garthe, Crossed currents . . . 969 Gas-absorption trough .... 516 - and vapour condensation (ex- periments with Looser's ther- moscope) 592 - and vapour densities . 613, 614 • -balance 367 — burette for demonstrations 220 - burners (Bunsen's) .... 208 - calorimeter 621 — cell 853 - Coulomb-meter 943 — dilatometer 575, 576 - distributing device see vol. I. — endosmose 410 — engine 629 — engines and dynamos, see vol. I. — flame manometer 284, 432, 433 — generating apparatus . . .213 — plant see vol. I, also vol. II, p. XV — harmonica 430 — igniting apparatus .... 825 — indicators 410 - lamps see vol. I. - measuring jar for voltameter 941 — meter 624 — calibrating device . . 624 - osmose, shown with Kolbe's thermoscope 598 - pressure governor .... 624 — see also vol. I. - regulator 860 - prism 502 - reaction wheel 407 — regulator 207, 208 - sodium lamp 562 - tap, Biernacki's 859 - thermometers .... 581 — 584 — voltameter 942 — washing flasks 220 Gaseous bodies, equilibrium, mo- tion and molecular effects 365—411 Gases, cooling action ... . . 406 - liquefied by pressure^ . . . . 359 Gasoline carburetter, see vol. I. Gasometers 211, 212 Gati, Bela, Baretter set .... 933 Gaugain, Tangent galvanometer 872 Gauges, barometric 401 — for wires and holes '.' '. . . 223 Gauss Stands 204, 205 Gay-Lussac, Apparatus for prov- ing Dalton's law .... 603 - Gas and vapour densities 613 — — Gas dilatometer. . . . 575 — — Law of gases 574 - Tension of water vapour 604 Gearing for laboratories .... 998 - for two intersecting axes. 322 Gearings with screws, cranks, links, rods, joints and discs . . 313—318 Gehrke-Lummer, Interference plate 507 - Interference spectro- scope 509 - Oscillograph tube 897 Geissler, Hypsometer 652 - Mercury air pump, demon- stration 365 - Mercury vacuum pump . . 397 - Spectrum tubes 515 — tubes 406, 830, 1014—1017 - for Zickler's opto-electric telegraphy 1053 See also the Subject-matter Index in vol. I. 70* 1108 Alphabetical Name and Subject-matter Index. Page Geissler, tubes with fluorescence phenomena 519 - tube rotating device . . . 286 Geitel: see Elster and Geitel Gelatine plates 516 — slabs as colour filters . . . 528 General gear system 319 — mechanics 251 — 264 — name and subject index . .1097 - use, apparatus and supplies 201—220 Generating a powerful induction current 1013 - apparatus for gas . . .213, XV - electricity by influence . . 806 - liquid air 610 - of alternating current . .1012 - of heat by current . .936 — 940 - of heat by mechanical work (experiments with Kolbe's thermoscope) 5P7 - of heat by mixing liquids 625 - of heat on freezing .... 600 Generator for carbonic f.cid . . 609 Gerdien (not Gerdium) Cylindrical condenser 834 Gardium, to be read Gerdien, Cy- lindrical condenser .... 834 German hoisting jack 330 - rapid balance 2-11 Geschoser, Extra current . . . 976 Geyser, models ...... 630, 631 Geysers see vol. I. Giifard, Injector model .... 637 Gilding apparatus 949 Glan's Prisms 566 Glan- Thompson Prisms . . . .565 < Mass discs with airspace for in'rr- ference phenomena . . . 544 - background see vol. I. — balloon for hanging to the whirling table . . . . . .281 - balloon with glycerine soap solution . 543 - bell, calibrated 211 - on wood base .... 443 — — with lead weight . . . 346 — with 4 pendulums . . 443 - block, Faraday's . . . 955, 956 — blowing tables see vol. I. - body after Kplbe 494 — floating in cold water . 345 ' ;ise for demonstration in- struments 901, 902 - -cases for setting on gas- exhauate, see vol. I. — -cocks 207 - cube 494 - cylinder for Beckmann's app. 615 - for the acoustic reaction wheel 4fi4 - cylinder with cooling ring . 573 - with heating device . 573 - drops, Batavian 312 — globe for showing Newton's rings 285 — gratings 548 - micrometer 537 - pearls 220 - piercing apparatus . . 828, 829 — plate column 554 - for refraction experi- ments 491 - for the Hall effect . .1026 I'm- the screening effect 812 - with letters and calc-spar plates 563 565 — plates 220, 1053 — for influence machines 823, 824 - with ;'ir Lrap 494 press ........ a.')!!. r,(14 Page Glass prisms 499, 500 — receiving cylinders . . . .216 - resonator '. . . . 449, 450, 464 — rods with amalgamated leather 814 - with glass balls 801, 1010 - slab 810 - for using Rosetti's ful- minating plate as a Frank- lin's plate 835 - sphere for weighing air . . 402 - with tube 567 — — with 2 stopcocks . . . 576 - spiral ..... .... 303 - stoppers 216 - tube for determining the spe- cifk gravity of gases . . 367 - for polarisation experi- ments 552 - for testing 857 - turning on isolated stand 798 - with iron filings . . . 789 - with mount, closed by rock salt slabs 646 - with platinum lugs . . 512 - vessel, cracked spiral shape 303 - for mercury and coloured water ?81 - spare 852 - with 6 receivers . . . 599 - with ether and alcohol . . 612 Globe on insulated stand . . . 822 - terrestrial 660 Glow lamp 452 - filament 523 - in receiver . .406, 996 - for mirror and lens ex- periments 473 - holders and lens mount 499 - for the Edison effect .1026 - for thermal and total energy 937 - for thermal conduction and convection 641 - photometer 470 - resistance 899 - ring, Grimsehl's . . . 478 — stand 995 — stand with Edison socket 973 - lamps 995, 996 - (comparison lamps) 470, 471 — with holders 935 - light oscillograph tube. . . 897 Glycerine-clay-sphere 281 Glycerin-water mixtures .... 485 Gnomon 229, 244 Gocht, Alarm clock 245 Goerz, Trie'der binoculars . . . 540 Gold leaves between glass plates 544 Goldschmidt, Levelling baro- meter 376 Goldstein Tubes 1022, 1023 Goniometer for aperture-angle . 466 - for optical demonstrations 47!). 480 - for students' use 480 Goniometers .... 229, 479 — 482 Gooch, link 316 Gore's Ball 627 Gotschlich, Aperture goniometer 466 Gotze, Magnetic field . . .964, 965 .Magnet stand and movable armature coil 988 - Ohm's law, explaining. . . 917 - Parallel >u helium of conduc- tors 917 - Rotary solenoid 968 - Synchronism and a-\ n elinmisin 1004 Goubet's Coupling 317 (Jovernor. centrifugal (Watt's) 3Hi.li:;7 Graduated circle for telescope . 543 Page Graduating an electrometer . . sin Gramme-Pacinotti-Machine . . . 289 Gramme, Ring armature .987 — 991 Gramophone 461 Graphic reproduction of current curves 897 — 900 Graphite conductor 803 - crucibles 939 — dish 218 - sliding resistances see vol. I. Grassmann, Vacuum pump stop- cock :is; Grating spectroscope . . . 509, 5lo Gratings for diffraction experi- ments 548, 549 S 'Gravesande, Elasticity of wires 303 - Parallelogram of forces . . 2(>1 — Sphere with ring 567 Gravitation balance ::uo Gravity, centre . . . 267, 274, 275 - specific 342 — 350 — specific of gases 367 — tester . 857 Gray, Gyrostat 2!»1 Greiner and Friedrichs, Mercury vacuum pump 397 Grenet, Bottle cell 84!» Grimsehl. Aluminium leaf electro- meter sn-j - Analyzing apparatus for vi- brations 3i MI - Auxiliary apparatus for de- monstrating the calc sp-n- cross 5.vj - Bar machine s ! .", - Built-up model of lenses. . 4'.M - Bnnsen-burner with pan and cylinder for reversing the sodium line .11* - Carbon filament lamp . . . !MH> - Coil for generating a homo- geneous magnetic field . .1012 - Collimator tube with micro meter gap 51.'! - Colour ring apparatus for determining wave length . 544 - Composition of motions . . 25S - Concentration cells .... !M7 - Copper and zinc plates . . 839 — Cryophorus ........ 608 - Decomposition cells .... 944 — Demonstration analyser . . 552 - Demonstration polarisation apparatus 552 - Demonstration polariser . . 5."i I — Detachable tangent galvano- meter NT-' - Determining wave length of light 5»5, 5».s - Dielectric constants . . . . !i:!5 - Double gun 252 - Dropping vessel for mercury 215 - Electric air thermometer . S2!» - Electric equivalent of heat !K!7 - Electrolytic apparatus 9-1.'!. !Mt - Electrolytic conduction . . . '.'_".> - Electrolytic demonstration t apparatus 945 - Electromagnet with foot ter- minals 1012 - Kxciter for stationary wire waves 1"! I - Kxpcrimcntal introduction of electromagnetic units 1010— 1013 Kvplainini; tin' dynamo . . !iss - Fillet with 2 lens mount-- in* - Folding cell M7 l-'rcsncl's mirror for student's UM' 545 - Gas balance 3(i7 - Glass tube for polarisation experiments 552 See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1109 Page Grimsehl, Glow lamp model . . 996 - Glow lamp ring 478 — lamps for thermal con- duction and convection ex- periments 641 - Goniometer and spectrum apparatus 481 - Graphite conductor .... 803 - Hertz' fundamental experi- ments 1038 - Hot wire ammeter for demon- stration 905 - Influence of temperature on resistance 913 - Interference apparatus. . . 545 - Joule's law 937 - Lantern with Xernst lamp 513 - Magnetic pole balance . .1010 - Mechanical equivalent of heat 627 - Model of a gypsum membrane 562 — shewing the passage of converging polarised light through a calc-spar plate. 562 - Moment of inertia apparatus 290 - Nernst lamp for demonstra- tion . 995 - Optical eye 523 - Oscillation analysing appa- ratus 837 - Overflow vessel 250 - Piezometer 358 - Pistol for determination of mass 252 - Pistol, target and stand for studying the trajectory . 263 - Polarisation apparatus for student's use 554 - Polarisation in double re- fracting substances . . . 562 - Pole balance 796, 801 - determining cell . . .1012 - Projection (Cosine theory) of mechanics 260 - Rainbow apparatus .... 503 - Reaction cannon 260 - Refraction and reflection ap- paratus 485 - Reversing the sodium and strontium line 518 - Screw apparatus 273 - Shunting small potential dif- ferences 1013 - Synthesis of vibration . .417 - Tensive and compressive strain 269 - Thermal and total energy. 937 - Tone manometer 429 - U-shaped decomposition ves- sel 944 - Vertical rule 222 - Voltameters 942 - Wave motions 413 Grimsehl-Rebenstqrfl, Compensa- ted water dilato meter . . 572 <;Hps with connecting leads . . 973 Grooved glass with electrodes . 943 Grove, Batteiy 853 - Cell 849 — Gas cell 853 - Thermal conduction of gases 641 Uriiol. Klectric tourbillion . . . 828 Gruey, Polygonal pendulum . . 293 Guide, Peaucellier's 316 (inides with 2 cranks 324 Gillcher, Thermopile 859 van Gulik, Doppler's principle . 283 Gun, activated by compressed air 410 - double -!•">- Gunpowder, action 626 • •vpsum and mica combination. .">(>."> - plates r>3s Page Gypsum membrane, model . . 562 — • figures . 565 — star and butterfly . . 560 - plates for complementary co- lours .... 560 — preparations ..... 564, 565 — slab 596, 597 - and heating rod . . . 639 — wedge 564 - with movable hyperbolae . 560 Gyroscope, Foucault's 298 Gyroscopes 291, 292 Gyroscopic Tree, oscillating . . 293 Gyrostat 291 H Haedicke, Float 344 - Metacentre and buoyancy . 345 Hagen, Antivibration suspension of galvanometer 884 - Mercury vacuum pump . . 397 Hagenbach, Angle of elevation . 263 Hahn, Electric calorimeter . . 936 — Monochord 441 - Recording device (frequency of a tuning fork) .... 455 - Tangent galvanometer . .871 - Wheats tone slide wire bridge 919 Haidinger, Dichroscopic magnifier 563 - Interference-ring-system . . 506 Haldat, Pressure of liquids . .341 Half cylinder for the metacentre 345 - lenses, Billet's 546 — ring electromagnet . . 954, 956 Hall effect 1026 Haller, Celestial globe 661 Hallwachs, Differential prism . 502 Hamilton, Conic refraction . . 564 Hammer for striking tuning forks 439, 440 Hammerl. Passage of current in the Gramme ring .... 989 Hand balances 241 - regulation for projection lan- terns, see vol. I. — regulator for arc-light . . . 1057 — see also vol. I. — tachometer 999 - telescopes 540 Handles for induction coils . . 974 Hanging board for apparatus and galvanometers, see vol. I. Hankel, Electrometer 841 Hann, Psychrometer tables . . 655 Hardness scale 312,1069 - tests: see emery disc . . .281 Harmonica, chemical 430 Harmonic vibration .... 298, 299 Harris, Lightning conductor . . 835 Hartl, Apparatus for the liquid pressure 340 - Centrifugal pump and blower 282 - Commutator 867 - Comparison of superficial colours 544 - Curvilinear path of the rays 485 - Draining and drying appa- ratus 282 - Float 345 - Foucault's gyroscope . . . 298 - Glass box for total reflection 494 - Glow lamp filament in re- ceiver 406, 996 - Indicating balance .... 240 - Molecule model . . . . . 301 - Moment of inertia .... 289 - Optical disc 488—490 - Outflow apparatus .... 351 - Pressure increase apparatus 339 - Projectile apparatus . . . 263 Page Hartl, Reaction apparatus . . . 352 - Recording the parallelograms of motion 259 - Repulsion apparatus . . . 407 - Screw apparatus ..... 273 - Simple polarisation appara- tus 354 - Stable and unstable axes . 282 - Torsion moment and con- ditions of equilibrium . . 270 - Total and partial reflection 494 - Tribometer 301 - Wedge apparatus 272 Hartwich, Hydrostatic paradox 334, 341 Hausser, Lenard's phosphoroscope 520 Hauy, Electricity produced by temperature changes or pressure 838 Heart model 1069 - shaped slot 318 — -treatment with X-rays and high frequency: see special list. Heat 567—649 - and work 626 — 637 - and work (experiments with Kolbe's thermoscope) . . 597 - and work (experiments with Looser's thermoscope) . .591 - engines 629 — 637 - equivalent, electric . . 936, 937 - experiments with Kolbe's thermoscope 595 - from chemical combinations (Looser's thermoscope) . . 593 - generated by mixing liquids 625 - in the internal and external circuit 846, 847 - mechanical .... 285, 286, 627 — of combustion . . . .622 — 625 - of neutralisation 625 - of vapourisation 621 - propagation 638 — 648 - reflection in vacuo .... 406 - supply for radiant heat . . 649 Heating apparatus for calorime- tric experiments 617 - boxes for paraffin embed- dings, prices on application - effects of electric current936 — 940 — effect of electric current (with Kolbe's thermoscope) . . 599 - of electric current (with Looser's thermoscope) . . 593 — of mercury by electric cur- rent 937 Heavy current fuses, action of 938 - multiple commutator. 869 Hefner, Standard lamp . . . .471 Heil, Dynaphor 860, XV (cannot be furnished) Heilbrun, Telephonic lecture in- struments 1055 Heim, Discharge key 868 Heliographs for signalling. Parti- culars on application. Ileliostats see vol. I. - with solar microscope . 539, 540 Heliotrop after Steinheil . . . 483 Helium tubes 515, 1045 Hellesen dry cells 850 Hellmann, Rain Gauge .... 657 v. Helmholtz, Double siren . 422, 423 - Kcsonators 450, 451 - Vibration microscope . . . 457 - Vowal apparatus . . . 459, 460 Hematometer 538 Hemispheres of Magdeburg . . 402 Hemispherical-ended cylinder. . 806 Henley, Discharger 835 - Quadrant electrometer . . 828 See also the Subject-matter Index in vol. I. 1110 Alphabetical Name and Subject-matter Index. Page Henniger, Kft'usiometer . . . .411 Heron's Ball . . 334. 381, 382, 404 — — explained 366 Fountain 382 - Rotating ball (sphere) 407, 630 Herschel, Solar prism 543 - — Telescope demonstrated . .531 Hertz, Electric power rays . .1039 Hertzian \Vave transmitter . .1041 - waves, wave machine . . . 412 Hesehus, Spring balance (dyna- mometer) 310 Hessian crucibles 218 Heumann, Striation apparatus . 364 Hexano gas generator see vol. I. Heydweiller, Mirror electrometer 844 Heylandt, Geneiating liquid air 610 High-capacity influence machines 822, 823 — frequency and tension appa- ratus (Tesla's) . . .1030—1035 - apparatus for Arsonvali- sation and other therapeu- tical purposes, see special list - pressure iron boiler .... 634 - tension battery 811 — — rheostat 924 - transformerl031, 1032, 1038 — -vacuum pumps 390—394, 397—399 - voltage accumulator battery 856 Hillig, Electrolytic demonstration apparatus 945 - Pendulum apparatus . . . 296 — Wave machine 413 Hipp's Chronoscope 248 Hittorff's Tube 1016 Hoffmann, Diffraction apparatus for determining wave length 548 Hofler, Rail apparatus (inclined plane) 253, 258 Hohnann, Faraday's second law 944 - Combination of hydrogen and oxygen 945 - Pocket spectroscope . . . 511 — Vapour density 614 - Voltameter 942 Hofrnann-Janssen, Spectroscope 509 Hoisting and transporting ma- chines (models) . . .328—332 — devices for maps, plans, see vol. I. — jack 330 Holder for candle .... 812, 813 - for carrying crystal and gyp- sum plates 646 - for conductivity vessel . . 930 - for fluorescent cubes . . . 518 - for Franklin electrode . . . 822 — for porcelain dishes and cru- cibles 217 - for retorts 203 with, terminals 996 Hollow balls 812 - ball for electrometer . 802, 812 — copper ring with tube . . 1009 _ cube 230 - of crystal glass .... 612 - cylinder for balloon experi- ments 368 - cylinder for showing free electricity 807 - cylinder of sheet brass . . KO9 - hemisphere and plane plate Jin - iron sphere with closing scnu lioo — lenses •*!'•) - polished metal sphere . . . lOi prisms 501, .")(>•_' - prism after Silbermann . . 491 - sphere on insulating handle 806 Page Holtz, Demonstration galvano- meters 875 - Foot or stand clamp 799,866, 1010 - Influence machines, seeWims- hurst machine. . . .819 — 821 - Tube 1016 Hook with cramp 266 Hook's Gearing 322 Hooked weights 261, XV Hope, Stratification of aqueous masses 573 Hopkin, Experiment on resonance 442 Horizon 661 Horizontal component of terres- trial magnetism 796 - galvanoscopes 876 — 884 - gas engines 629, 630 - intensity of terrestrial mag- netism 796 - pendulum 768 - projection apparatus see vol. I. Hprizontarium 662 Hermann. Commutator .... 867 Horn with reed 429, 464 — •without reed 427, 464 Horse-hair, longitudinally vibrat- ing 442 Horseshoe electromagnet. . 950, 973 - magnets 785, 786 - magnet with homogeneous field 789 - magnet with induction coil 971 Horst'ord. Conducting resistance of liquids 929 Hose unions 207 Hot water heating model . . . 574 — wire instruments 907 - instrument, principle 904, 905 House and its perspective image 529 - with tower and lightning conductor 836 Hrabowsky, Tension and accele- ration apparatus .... 257 Huber, Boyle's (Mariotte's) law 379 Hughes, Microphone 1054 Human beings' breathing . . . 408 — eye, explaining 496 Hummel-Schuckert Ammeter. . 905 Huyghenian construction of pheno- mena in crystals .... 563 Hydraulic analogon of the Leyden jar 837 — bellows 336 — press . . . 334, 337, 338, XV — ram 334, 353, 354 Hydririn generator see vol. I. Hydrodynamical explanation of current 917 Hydrogen, bombs for, see vol. I. Hydrometer .... 237, 346, 348 Hydrometer for accumulators . 857 - for showing maximum den- sity of water 573 Hydrostatic apparatus . . 334, 336 — balances 238 - paradox 341 Hygrometers .... 652 — 654, s •_'.". Hyperbolical toothed wheels . . 323 II ypocycloid formation .... 318 llypocycloidal gear system. . .319 Ilypsoineter 580, 652 Hypsometric thermometer . . . 578 I beam with traveller see vol. I. Ice-breaking machine (>ol - calorimeter 616, 617 - chopper 214 evaporating 608 — forming 405 Page Ice machines 214. HIM i - melting ~>7 1 - producing by evaporation i>o7,(>os Igniting ether 813, s-_'i; — gases s •_'."> - the vapour of alcohol . . . 'Jsr, Illuminating gas, testing appa- ratus. Ask for quotations. - lens .V!1.) I Humiliation and colour impression 529 Illusions, optical 5-Js Immersion batteries . . . 851. s:>j — body, indifferent 354 - tubes :',(!! Impact pressure of liquids 353. 354 Incandescent gas burner with chimney 878 — gas lamp 474 - lamp 843 - vapour spectra . . . .512 — 515 Incidence of light, measuring . . 4M; Inclination apparatus 7!>o - explained 789. Tim Inclined Plane 257, 258, 267, --'(is Incomplete journal :ilJ Increase of pressure downward- 338, :::!!i — of volume when water freezes (>oo Indefinite forces 305 Index, alphabetic 1097 Indiarubber balloon :i»i(i - cords 414 Indicating apparatus .~>.'i7 - balances 24O Indicator cylinder 223 — for resistance thermometers 58(> - for resonance vibrations. . 838 - for specific gravity .... 347 — of direction of field. . . . 79o — of gases 41o — of induction, automatic . . 971 Indices of refraction 48(> Indifferent equilibrium . . 273, 274 — immersion body 354 Individual periodicity of a system 297 Indrikson, Thermopile .... 1074 Induced radioactivity 1027 Inducing and induced electricity 804—808 Induction apparatus with buzzing sound 93(> — — • with tuning fork inter- rupting 92S — coils . 974, 978 — 982, 1058, XV — and bar magnet . . . U7L' — — and horse-shoe magnet . 97 1 — — flat 955 — — for calibrating ballistic galvanometers 97*> - coils for measuring electro- lytic resistances 886 — coils for Thomson's experi ment 1058 - coils with interrupters . .981 - without interrupter . . 980 - commutator 981 — currents 971 — 1013 - indicator '.'7 1 — measured '•'•'!."> - spirals 813, HKi: - unipolar Inductive effect of discharge shock S2!i - repulsion 1008—1010 Inequality of surface tension 363. '.Mi, Inertia, demonstration .... L'5 1 — moment 289. --".HI - of water 339 — pendulum -•"' ' - to]> 251 Influence electricity Sod - machines . .' 81(5—823. 1072 — machine, model . . . 813, S17 See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter 1111 Page Influence of temperature on re- sistance 912, 9) Ingenhouss, Thermal conduction 638 Injector, model 408, 03 / Ink writer, Morse's J5J Inset for piezometer 359, 603, 607, 613 Instructional model of a gas engine ]**«• Insulated translator pillar . . . « — wire fork \ Insulating stand . . . 798, 799, 829 — stool °25 - table of ebonite 80.* Intensifying screens 1074 Intensity of field, measuring. . I _ of fight 465—474 Interchangeable coil with tube suspension. ....••• 888 Interference and diffraction 543—550, 556, 560, XV — images 490 — mechanism <>25 _ minor 544, 545 — after Fresnel 561 _ of sound 461, 462 of wave motions . . .413 — 41 / _ plate 507 — prism (Fresnel's) 546 544 506 509 Page Iron stink cupboards see vol. I. — tables, see vol. I. — weights calibrated .... 244 — weights with hooks . . . .441 _ wire mantle for glowing char- coal 643 Irradiation of the moon's crescent 525 Isochromatic wave surfaces, mo- dels 563 Ives, Diffraction chromoecope. . 550 see also vol. I. — Projection chromoscope . . 529 Ivory ball with marble slab . . 302 hammer for tuning forks . 440 — ring system, Haidinger's. — spectroscope - sec interference plate. . 50/ Intermittent fountain ..... 382 — wheel with external and in- ternal teeth ....... 326 Intel nal combustion engines see vol. I. — friction of liquids . . • • ^ — heat of cells 840 — toothed wheels . . . .319, 320 International Weston standaid cell 845 Interrupter, electrolytic . . . . * Interrupters = — for induction coils. . .982—984 Interrupter, Wehnelt's . 1010, XV Interrupting wheel - Interval apparatus .... 447, 44, Intrinsic brilliancy, measuring. 467 Introduction to Physics . . . . 250 - to the experiments with Kol- be's thermoscope 595 to the use of Looser's ther- moscope (in German) . . . 589 Invariability of static momentum 26£ - volume of liquids .... 3 Inverted float 380 Investigating metal spectra . . B Involute formation 31i — gear system •_ • j- — system for rack and pinion 3 Iodine tubes 601 lonisation of air — by Roentgen rays. 1025 Ion's migration velocity . . 944, 940 Iron and steel bars .787 - bar on stand and two wire spirals 950 - with copper wire winding 972 — base for measuring instiu- ments 907 — clad galvanometer .... 884 - dish 217 — filings "89 — -free lecture table see vol. I. - museum cupboards see vol. I. — powder 789 - ring for making ring arma- ture 991 — ring with wire turns . . • * - sphere (explosion ball). — stands and double cone Jablcchkoff's Candle Jack with 3 legs Jamin, Absorption of liquids by porous bodies — Circle — Laminated magnet .... Janssen-Hofrnann, Spectroscope Japanese mirror Jars for powder Jelinek, Psychrometer tables. . Jet interrupter — of water is composed of drops Joiner's tools see vol. I. Joint of copper and zinc . . . Jolly, Air thermometer .... — Spring balance Jolting and expansion .... Joly, Diffusion photometer. . . Jonval Turbine Joule, Electromagnet — Law 936, - Mechanical equivalent of heat Journal with bearing Journals' friction Jug, magic Jung, Microtome cutter . . . . Junkers, Calorimeter for techni- cal calorific value determi- nations 996 330 364 499 78c S09 478 21 t t * 351 f 582 309 3 4 356 951 937 312 302 380 600 810 Kaehler, Burette stand .... 203 Kahlbaum, Constant action mer- cury vacuum pump ... 2 Kaleidophone 451 Kaleidoscopes 476 - for polarised light .... £ Kann, Copper stirrup 103 — Joule's law . . . . . • • • 937 Proving self-induction . . . 976 Kater, Reversing pendulum . . 295 Kepler, Light refraction apparatus 485 Kettle enamelled for the volati- sation of ammonium nitrate 214 Key, electric .... 86e— 868, 930 for Wheat stone bridge. . . 919 — for wireless telegraphy appa- ratus !052 — Morse's 960 — with mercuiy contact . . . 867 Kienrnayer, Amalgam • ••••* Kiessling, Parchment strips . . 7»9 Kinegraph • • 259, XV Kinetic deteimination of mass . 25^ Kinnersley, Electric thermometer 8 Kipp, Gas generating apparatus 213 Kirchhoif, Law 911~~9?l — Table of spectra 518 Kirchhoii-Thomson, Electrometer balance S44 Page Kitchen balance 3 Kitller, Standard cell jj Kleiler, Duplex barometer ... 372 — Electric balance * Lateral pressure apparatus 3 — Magnetic balance 79£ Universal spring balance . . 3 Knapp, Ophthalmotrope .... 522 Kccb, Single phase alternating current rectifier 8t>2 Koenig, Inclined plane .... 2 Manometric flame pipe . . 4 Massive forks with stand . 4 Sound analysis apparatus . 4 — Tone impact apparatus . . — Wave siren Koenigsberger, Direct vision prism o02 (580) Kohl, High-VacnumoPumpS39__399 Motor mercury interrupter . 983 — Rotary mercuiy high vacuum pump 398, 3 Kb'hler, Electric thunder cloud . 827 Kohlrausch, Bridge \ — Condenser °AA — Demonstration ammeter and voltmeter * — Electrolytic resistances . . 886 — Electi ometer 801 — Resistance vessel 8 — Total reflectometer .... 499 — Universal bridge £ Velocity of migration of ions 946 — Voltameter 942 Kolbe, Aluminium electrometer 802, 80J — Aluminium leaf electroscope 800 — Ampere's stand ..... — Automatic current-direction indicator £ — Auxiliary electroscope . . . £ — Coloured cylinders .... 2 — Condenser 833 — Conductor ', \ — Constant cell , « Current circuit fall trough . 248 — Current conductor .... 950 Cylindrical bodies of the same weight 350 — Demonstration barometer tube 371 — Demonstration photometers 467 — Differential and double thermoscope 595 — Electro-dynamic double pen- dulum s — Electrometer .... 802, 8 — Electrostatic apparatus 811— — Experiments on induction . S — Flexible wire netting . . . 811 Gas voltameter 945 — Glass body 4 — Hofmann voltameter Inductive effect of discharge shock 829 — Insulated wire fork . . . . * — Key with mercuiy contact. 867 — Light -refraction apparatus . 4 — Mach's optical apparatus — Model of moving coil galva- nometer Jj — Paper electroscope .... 79S — Pressure terminals .... 866 — Projection cell 846 — Reflection and refraction in water 485 — Rheostat for relative resis- tance 913 School pattern Wheatstone bridge * — School rheostat 914 See also the Subject-matter Index in vo . I. 1112 Alphabetical Name and Subject-matter Index. Page Kolba, Sextuple manometer . . 599 - Small voltaic cell 845 — Specific heat apparatus . . 6 IB - Steatite piece 797 - Tangent galvanometer . . . 872 - Testing electroscope .... 802 - Tliermoscope 595 - Trough cell 847 - Universal stand $68, XV Kolosy, Compression hygrometer 654 Kommerell, Power shunt . . . 893 Koneck, Steel cylinder for calori- metric experiments .... 623 Kbnig, Comparing two tones of pipes 462 - Phonautograph 456 - Sensitive flame burner . .418 — Wave siren disc . . 283, 420 Kopp, Calorimeter 619 Koppe, Capillary hygrometer . . 653 - Curve top 292 - Rotational and successive motion 282 Korn, Phototelegraphy .... 932 Kbrner, Model of molecule 301, 567 Korolkow, Absolute electrometer 804 Kottenbach, Fall apparatus . . 256 Krajevitch, Syphon barometer . 373 Krebs, Distributing apparatus . 806 Kvoeker, Calorimeter for deter- mining combustion heat . 625 Kriiger and Dolezalek, Current flowing through a liquid . 848 Krupp, Gun trajectory .... 264 Kriiss, Optical flame measuring apparatus : see Hefner lamps 47 1 Kiihne, Optical eye 523 Kiuidt. Covered pipe 428 - Dust figure apparatus . . . 434 - Manometer 419 - Manometer in Trussevitch stopcock-arrangement . . 598 - Pyro-electric apparatus . . 838 Kunzi'te 1027 Kurlbaum, Bolometer 648 Kurz. Moment of inertia . . . 289 Labial pipes 426—429 Laboratory equipment see vol. I. - furnaces, electrically heated 940 - galvanometer 889 - microscope 536 - stand 205 - switchboards, see vol. I. - tables, see vol. I. La Cour, Phonic wheel .... 463 MI: and leading current prod- uced 900 Lahire Guides 324 Lalande Cell 849 Lambert, Demonstration photo- meter 467 Lambrecht, Aspiration psychro- graph 655 - Aspiration psychrometer . . 655 - 1'olymerer 653 - Weather telegraph .... 654 Laminated magnet 786 - mirror 504 Lamont, Earth thermometer . . 650 Lamp, Locatelli's 645 - reading apparatus 896 - resistance 858, 899 — see also vol. I. - for experiments with Kolbe's thennoscope . . . 598 Lamps for reflecting galvano- meters S7H - with slotted chimney . - • 84:5 Page Landolt, Elongation of paladium • on absorbing' hydrogen . . 853 - Vacuum gauge 368 Lane, Measuring jar 833 v. Lang, Projection polarisation apparatus 553 - Spectrometer 506 Lantern slide of the curve of maximum density .... 573 Lantern slide of the trajectory 264 - slides for explaining alter- nating machines 1001 — for explaining wave motions . 413 — — of all branches of science. Please write for list. — wheels . . . 321 - with Nernst lamp 513 Laplace and Lavoisier, Linear expansion coefficient . . .571 Laplace, Ice calorimeter . . . . 616 Lapsometer 256 Large brass conductor 1033 Large optical bench for inter- ference and diffraction ex- periments 547 - photometer bench 470 - tuning forks with sliding weights 438 Larynx, models 444 Lateral pressure apparatus . . . 353 Lathe, see vol. I. Lavoisier and Laplace, Linear ex- pansion coefficient . . . .571 Lavoisier, Ice calorimeter . . . 616 Laws of magnetic induction . .971 - of mechanics, collection of apparatus 265 - of pendulum 260 - of reflection 474 Lead balls and hardwood balls . 302 - base, copper and zinc strips 839 — cap for electroscope .... 808 - plate and ether thermometer for the piezometer .... 359 - plate on ebonite rod . . . 814 - plate with hammer and por- celain bowl 612 Leads, connecting 822 — flexible 206 — heavy current on lecture table, see vol. I. Leading and lagging current prod- uced 900 Leaf electrometer .... 810, 812 - electroscopes 1025 Leaning Tower 274 Leather rubber, amalgamated, see ebonite rod 812 Le Chatelier, Electric pyrometer 584 Lecher, Stationary electric waves 1043, 1044 - Tube 1044 Leclanche Cell 850 Lecture electrometer 803 - galvanometer 881 - room equipment, see vol. I. Leduc, Cohesion and adhesion tube 361. 4(ir. Leduc-Regnault, Differential baro- meter 370 Lehmann, Crystallisation micro- scope 536 — Paper electroscope .... T'.i'.i Tube for demonstrating va- pour tension 604 Leidenfrost's Experiment . . . 602 Lelande, Cell, to be read Lalande cell 849 Page Lenard, Bismuth spiral .... '.ir.r. - Phoshoroscope ,~>2(i Lengths, measuring . . . .221 — 228 Lens apparatus 496 — cylindrical 560 — disc after Boys . . . 526, 837 — holder 473 — of short focal length . . . 546 - on stand !(()() — stands 496 Lenses arranged in dioptres . . 498 — concave and convex . . 494, XV — condensing and dispersing, demonstrated 488 - for radiophone 649 - for telescope and microscope demonstrations 473 — in case 495 — of rock salt 646 Lermantoff, Caloriscope . . . .936 - Properties of gases . . . .365 Leslie, Cube for showing different emission of heat 646 - Differential thermometer . 588 Letter and Sorting balance . .241 Levelling barometer 376 — board 205, 206 Level model 335 - quadrant 483 Lever apparatus 270 - bent 315 — equal armed 269 — of aluminium 2(>5 — stand 270, 275 — switches 866 Leyden jar 810, 830—832, 836, 1025, 1033, 1035, 1038 — — battery . 832, 1030, 1072 - for Coolidge-Blondlot's apparatus 1044 - for resonance experi- ments 838 — — with test ball . . . . si is Lichtenecker, Optical eye . . . 523 — Stability parallelepiped . . 275 Liebig, Cooler 21 o Liebreich, Ice machine .... 214 Light-angle-measurer 465 Light magnet system for galvano- meter 883 — propagation and intensity . -)(>•"> -reflection 474 — 483 - refraction 483—499 Lighting, electric .... 995, 996 Lightning arrester test apparatus 928 - conductor 835, 836 Ligroin lamps 531 Limatura ferri alcoholisata . . . 789 Limelight apparatus: sec vol. I. — punetiform 473 Limit, elastic 311 Limits of audibility . . . 439, 444 Linde's Machine, plate of sketches 610 Linear bolometer 648 — expansion 568—571 - thermopile 647 — vernier model 22 1 Lines elastic 306 - FraunhoJer s. demonstration 504 — of force, electric 788, 8 1 3, 830, 1010 — of force, theory. . . .962- -!'>,:, — of spectra 560 Links 316 Linnemann, Thorium light burner, M6 vol. I. Lippich, 1'olarisatioii apparatus 561. 562 Lippmann, Capillary electrometer 946 I lUcharge and mechanical motion 837 See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1113 Page Lippmaim Equality of induced and inducing electricity and screen action 808 Liquefaction of gases . . .608 — 613 Liquefying ice 601 Liquid air generated 610 - carried over to the negative pole 945 - films, vibrating 443 - prisms 501, 502 - prism, Wernicke's 560 — resistance 1024 - for electrometer leaf . 803 Liquids endeavour to contract . 361 — of different specific gravity 350 Liquid resistance 929 — 933 Lissajous' Vibration curves 451 — 455 Listing-Abbe, Refracting indices 479 Literature, abbreviations . . VIII Litre vessel 230 Lloyd, Conic refraction .... 564 Locatelli, Lamp 645 Lock up cupboards for influence machines 824 Locomotive, models 637 Lodestone 785 Lodge, Leyden jar 836 - Leyden jar for resonance experiments 838 - Resonance experiment . . . 1035 Loessner's Evaporation apparatus 210 Logarithmic spiral, wheels shaped according to it 321 v. Lommel, Reflecting stephano- scope 550 Longitudinal dividing engines 227, 228 - vibration of bars 433 - waves 411 — 417 Longitudinally vibrating horse- hair 448 Long stem thermometer .... 578 Loose pulleys 271 Looser, Dew point finder . . . 594 - Double thermoscope. . . . 589 - Thermal conduction appa- ratus 639 Looser-Dubrofski, Aspirator action 598 Lorenz, Double pendulum . . . 297 Loud speaking telephone . . .1056 Lowe, Psychrometer 656 Lowering of melting point . . . 607 - of the melting point of water 359 Lowest position of boiling point 606 Low pressure water lead, see vol. I. Lowy, Projectile apparatus . . 262 Luhrne, Pipette 381 Luminosity of places . . 465, 466 Luminous index 872 - intensity and angle of in- cidence 474 - needle 795 - sphere, Thomson's . . . .1024 Lummer, Bolometer 648 Lummer-Brodhun, Photometer head 469 (467) Lummer-Gehrcke, Interference plate 507 - Interference spectro- scope 509 Lummer-Straubel, Mercury arc lamp 515 Lunarion 662 Lustre, stereoscopic 524 M Mac Farlane Moore, Vacuum tube illumination 1025 Mac Leod, Vacuum gauge . . . 370 Page Mace de Lepinay, Polariser and analyser 550 Mach, Commutating device see Cascade battery 832 - Density of electricity . . . 807 — Dielectric constants .... 838 - Light-refraction apparatus . 486 - Optical apparatus .... 498 - Organ pipe 433 - Pendulum apparatus . . . 297 - Polarisation apparatus . . 556 - Quadruple inclined plane. . 258 - Tare balances 236 - Wave machine 412 Machine elements . . . . 312, 313 - power, provision of, see vol. I. Maey's Work rail 252 Magazine, magnetic 786 Magdeburg hemispheres .... 402 Magic funnel 380 - jug 380 - mirror 475 - mirror (Japanese mirror) . 478 - pitcher 380 — tun 380 Magnesia capsules 939 Magnesite capsules 939 - crucibles 218, 939 Magnesium lamp 522 - sulphate 853 - tape 522 Magnet model, molecular . . . 788 — stand and movable armature coil 988 - suspension for iron clad gal- vanometer 884 - system for galvanometer. . 883 Magnetic and electric experiments with the goniometer . . .481 - balance 795 - curves 962 - detector (Marconi's) . . . 1053 - double pendulum 787 - effect of a discharge shock 829 - experiments 787 - field and short-circuited ar- mature 289 — hammer break 975 - induction 971 — 1013 - machine 973 - of magneto-electric ma- chines 987 - magazine 786 - needle 786 - with compass card . . 792 - with glas * tube .... 968 - pendulum 796 - pole balance 1010 Magnetising spiral 950 Magnetism 785 — 796 - of rotation 287, 977 Magnetized steel gives tones . . 420 Magnetizing ring after Elihu Thomson 1010 - for two-phase current. 899 Magneto-electric induction ma- chine 973 - electric machine 987 - electric principle 288, 987, 988 - generator 961, 962 Magnetometer 793, 794 Magnetometrical measurements . 877 Magnifier, dichroscopic .... 563 Magnifiers for thermometer of ca- lorimeter 624 Magnifying glass 530 - with cross-wires. . . . 227 Magnus, Liquefying gases . 359, 613 - Thermal conduction of gases 641 Mahler, Calorimeter for deter- mining calorific value of fuels .625 Page Mahler, Experiments on the theory of electrons 1025 Maltese cross 326 Malzl's Metronome 248 Mang, Apparatus for astronomi- cal geography 662 Manganin shunts and series resi- stance 885 Mangle gear 320, 321 — wheel 325 Manometer flame method for comparing two tones . . 462 - Kundt's 419 - tone manometer 429 Manometric experiments with Kol- be's thermoscope 598 — — with Looser's thermo- scope 594 - flame pipe 428 Map holders, see vol. I. Marble slab with ivory ball . . 302 Marconi, Magnetic detector . .1053 - Wireless telegraphy .... 1047 Marine chronometer 249 Mariotte's Bottle 380 — Law 365, 377—379 Martius-Matzdori, Stereoscopic lustre 525 Mascart, Insulating stand . . 798 - Quadrant electrometer. . . 841 Masked rotating slot and crank 325 Mass apparatus 251 — attraction 300 - determination 252 Masses, rotating, equalised . . 262 Massive tuning forks 435, 458, 464 Materials for general use .201 — 220 - (Miiller's) for general purposes 220 - various, for workshop, see vol. I. Mathematical instruction models. 1064 Mather- Ayrton, Mirror galvano- meter . 888, 889 Matrices 948 Matter-index 1097 Maximum density of water . . 573 - thermometers 579 Maxwell, Inertia pendulum . . 251 - Pendulum . 294 — Wave tube 336 Measurement of efficiency . . . 252 - of the velocity of light . . 465 - of time 244 — 250 Measuring accumulator . . 930, 933 - apparatus for the textile in- dustry see special list. - condensers 935 - cylinders .... 216, 217, 346 — flasks 219 — glasses with stopper. . . . 217 - jar, Lane's 833 - of lengths, angles, surfaces, and volumes . . . .221 — 230 — staff 223 - wire 930 Mechanical effects of sound 463, 464 - equivalent of heat 285, 286, 627 - models after prof. Eug.Meyer XIV see also the apparatus called under the name of Prof. Meyer's. - model for electrolysis . . . 945 Mechanically movable plates for illustrating dynamos and motors 990 Mechanics, demonstrations . .481 - general 251 — 264 - of liquids and gases .334 — 411 - of solids 265 — 333 Mechanic's tools, see vol. I. Medal reprints 948 Medical laboratory equipment see vol. I. See also the Subject-matter Index in vol. I. 1114 Alphabetical Name and Subject-matter Index. Page Medium-high water-drawing wheel 358 MeJfert, Pythagorean theorem ex- plained 1064 Megadiascopes, see vol. I. Megaphone 419 Megascopes see vol. I. Meidinger, Cell 850 - Draught apparatus .... 408 Melde, Universal kaleidophone . 451 - Wave apparatus 415 Melloni, Apparatus for experi- ments on heat i'4."> - Thermopile 646, 647, 1062, 1063 Melta lid 1029 Melting by pressure increase . .601 — capsules 939 - crucibles 938, 939 - furnaces, electric . . . 938 — 940 - in the magnetic field . . .953 — of ice 574 - point 607 - lowered by pressure . 359. Membrane phonautograph . . . 456 - pipe as model of the larynx 444 - reed pipe 429 - singing 1009 - valve 409 Membranes, vibrating . . . 442, 443 Mercadier, Radiophone .... 649 Mercurial barometer, recording . 377 - pressure gauges 369 - vacuum gauge ........ 369 Mercury 214 - arc lamp after Lummer- Straubel 515 - air pump . . . . . .397 — 399 - air pump, demonstration . . 365 — board 214 — calorimeter 619 - compensating pendulum for standard clock 247 - distilling apparatus .... 39!) — drop, migrating ..... 363 - expansion 574 - filtration apparatus .... 399 - gasometer 211 - high vacuum pump .... 399 - interrupters 983 — jet interrupter 984 — press 399 — resistance thermometer . . 937 - shower apparatus 403 - spectrum lamp 515 - supplies for work with m. 214, 215 - switch 867 - syphon 404 - thermometer and water ther- mometer 577 - trough 1009 - vacuum pumps . . . .397 — 399 — vapor lamp 1026 - vapor rectifier: 862 see also vol. I. Meridian circle, model . . . .531 Mermet and Delachanal, Spark tube 514 Metacentre and buoyancy . . . 345 Metal baronieteis 375 — 377 - beaker for graduatiiifiBraun's electrometer 803 - coating for rubber slab . . 822 - compensating pendulum for standard clock 247 - cube with hollow cube . . 230 - disc with insulating grip. .1073 - drum stick 44(1 — lovers 265, 269 - receiver 596 mils for conduction experi- ments 597 - split-re, nickeled ">ts stand for magnet stirrups. 884 "Page Metal strips 349, 350 - tubing 207 Metallic bodies for specific heat (i!7 - thermometer 581 Metastatic thermometer . . 578, 615 Meteorological apparatus. .650 — 660 - charts 660 Metre rule 221 Metronomes 248, 615 Meutzner, Breathing of human beings 408 - Eeflection of light .... 474 Meyer, Compound slide valve cy- linder 632 Meyer, Eugen, Bending model . 305 — Bent crankshaft 304 — Centre of gravity 267 — Crankshaft with moving parts 305 - Defoi mation of a parallel- epipedic body by shearing stresses 307 - Equilibrium conditions of the centrifugal goveinor . . . 316 - Mohr's law on the elastic line 306 — Regulator model, for demons- trating the surface law, increase of angular velocity with decreasing moment of inertia 277 - Resonance apparatus . . . 300 — Rivetting model 306 - Spring pendulum 297 - Statically indefinite forces on a bearing 305 - Surface principle . . .277, 290 - Transverse strength apparatus 304 Meyer, V., Air-displacement me- thod of determining vapour density 614 Meyerstein, Hollow prism . . .501 - Refractive indices . . . .47!' Mica and gypsum plate .... 538 — combinations 565 — condensers ...... 933, 934 — disc 810 - plates for condensers . . . 813 — preparations 564 — slab . 59G Michel, Resistance to breaking strain 30G Michelson, Echelon grating . . 507 Micro-balance 232 - gas burner 615 Micrometer for spark lengths 811, 834 - gauge 220 - ocular 537, 892 - for spectrometer . . . 506 - (ring micrometer) for tele- scopes 543 - screw-micrometer 225 Microphones 1054 Microphone for photophonic ap- paratus 1059 - for speaking arc lamp 1057, 1058 Microphony 1054 — 1060 Micro-photographic apparatus . 539 Microprojection, see vol. I. Microscopes 533 — 537 Microscope, demonstrating . . . 4!>7 — demonstration 473 — for circle dividing engine . i'L!S - for projections 560 See also vol. I. - for reading scales . . . 226, 227 - vibration in -l.">7. l-~>s Microscopic phenomena . . f>.~6, .Mil. - polarisation apparatus . . 5 .">.". leading electioineter. . . . Ml Microscopical preparations . . . 53S - specimens 540 Micmscopy lamps see vol. I. — tables see vol. I. Page Micro -telephone station . lo.v>. io,->n Microtomes ,537, f>:!s Microtome cutter alter .lung . .Tils - knife r>:is Middle-shot water wheel .... :!,">(> Migration of a drop of mercuiy 363, !M u - of ions "944, 946 Milk glass and plate glass scales s;i.~> Mill, Barker's 3.-,:! - Woltman's :;.v> Milli;:iiiineteis 7!> Mirror apparatus 504 — — (Fresnel's) .... 544, 54r> - arrangement after Porro . 475 — box, rotating . 284, 431, 898 — chamber with telescope . . 891 - demonstration . . . .475 — 478 - electrometer 844 - galvanometers . 877 — 884, 1013 - on stand 442 - reading model 230 — rotary 484 - rule • ... 221 — sextant 482, 483 — stereoscope 524 Mithof, Hygrometer 653 Mitre gearings 321, 322 Mitscherlich, Apparatus for per- manent spectra 513 - Gasometer 211 - Polarisation apparatus . . ."til Mixed colours -S4 Mixing coloured rays and mate- rial colours 528. 5J!» — heat <>•_'.-> - method calorimeters . . . (il'.i — of gases 41d - the spectrum colours . . . 504 Mixture of radium and zinc sul- phide 1027 Models anatomical 1069 Model for equalisation of rotating . masses L'I>_ - geyser 630. <;:u - of air and gas engines 62!(, l>:io - of balances 275, '27 - of circular vernier . . 228, •-'•_'!' - of compound microscope. . ">:!] - of controller 99S — of ciystals and diamonds 1067— KMiii - of dynamos 987— 991 - of ear 444 — of hot water heating . . . 574 — of human eye .... 522, .">_:! - of hydraulic press 33S - of larynx 444 — of linear verniers --1 - of machine elements and parts and of complete ma- chines 312— :m - of microphone station . .1055 nl minor reading L'.'io of minor sextant 482 — o molecule 301, 567 of pump 383 — 385 lit ship's screw :!57 - of steam engine . . .631 — (i.'!7 of stopcock for \ acmmi pumps :is7 of turbine 356, I!:. 7 of ventilator '-'>>- — of water meter 355 See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1115 Page Model Tables of toothed gears 318, 319 - theodolite 532 Modulus of Young 308 Mohr, Burettes 220, XV - Densimeter 348 - Hardness scale (Name reads correctly Mohs) 312 - Law on the elastic line . . 306 - Pillar tare balance .... 236 — Specific gravity balance . . 237 Mohs, Hardness scale . . 312, 1069 Molecular effects of gaseous bodies 410, 411 — — of liquids .... 358—365 - of solids 301—312 - magnet model 788 - weight determination . . . 615 Molecule model 301, 567 Moment of bending 304 - of inertia .... 277. 289, 290 — of torsion 270 Momentum, static 269 - theorem 269 Monochord 440, 441 Monochromatic light 512 Monophase alteinating current dynamo 992 — 994 Monsoons and cyclones, theory 286 Montgolfier, Hydraulic ram . . 353 Morin, Fall machine 256 Morse Ink writer 959 - for wireless tele- graphy 1049 - key 868, 960, 1049 - for 50 amp 1052 - Telegraph 958 — 960 Mortar 215 - electric 826 Moser, Breath figures 410 - Flow of current in three- phase leads 1005 Motion and forces . . . .251 — 264 Motions, compound, explained . 259 Motion of gases 386 — 409 — of heated air 576 - of liquids 350 — 358 - mechanical and discharge . 837 - rotational and successive . 282 Motor driving stand for influence machines 824 Motor, electromagnetic . . 957, 958 - electromagnetic, for Geissler tubes 958, 1017 - electrostatic 826, 827 - for gas, petrol, electricity etc. : see vol. I. — generators, see vol. I. - mercury interrupters . . . 983 Motz, Condenser 833 Moulds for ice regelation . . .601 Mounts for Nicol prism .... 565 Mousson, Apparatus for liquefy- ing ice 601 - Spectroscope 510 Mouthpiece, universal 420 Movable conductor after Miihlen- bein 968 Movement of the clock .... 333 - of the single images of both eyes 524 Moving coil galvanometers 884 — 892 - galvanometer, models . 886 - pointer galvanometer . 933 - magnet galvanometers 874 — 884 - system of galvanometer not withdrawable 904 Miihlenbein, Alternating action of currents and magnets 967, 968 - Burette for specific gravity determinations 346 - Light refraction apparatus 483 Page Miihlenbein, Model of convex and concave mirror 477 - Models of lenses 494 - Thermal conduction . . . 638 Miiller, Friedr. C. G., Action of gunpowder 626 — .Air thermometer 583 - Arbor wheel 270, 275 - Arc light 473 — Arrangement for elasticity, expansion and breaking tests 312 - Balance galvanometer . . . 875 - Boyle's (Mariotte's) law . . 378 - Breaking tests 311 - Calorific value of hydrogen 622 - Calorimeter vessel . . . .618 - Channel balance 342 - Closed iron ring with coils 991 - Compass 793 - Conductivity of electrolytes 929 — Crossed currents 968 - Dasymeter (baroscope) . . 402 - Demonstration thermometer 577 - Dilatation thermometer . . 588 - Diminution of pressure appa- ratus 354 - Distribution of pressure . . 336 - Dropping apparatus . . . 362 — Drum rheostat 916 - Duplex pressure gauge . . 369 — Dynmeter 795 — . Earth inductor 972 - Electrodynamic action . . 967 - Equipment of class rooms: see vol. I. - Experimental barometer . 372 - Fall machine 256 - Friction brake 332 - Friction on journals .... 302 - Gas dilatometer 576 - Grooved glass with electrodes 943 - Heating of mercury by the electric current 937 - High pressure iron boiler . 634 - Hofmann voltameter . . . 942 - Horse-shoe magnet with in- duction coil 971 - Hydrostatic apparatus. . . 336 - Immersion tubes 349 - Inclined plane .... 258, 268 - Indicator cylinder .... 223 - Inductive effect of discharge 829 - Iron ring for making ring at mature 991 - Lecture table: see vol. I. - Lever stand 275 - Lines of force image . 964, 965 - Luminous index 872 - Luminous needle 795 — Magneto electric machine . 987 - Mercury resistance thermo- meter 937 - Model of a moving coil galvanometer with bifilar suspension 886 - Model of a multiplier . . .876 - Multiplication effect . . . 965 - Optical bench ....... 473 - Osmose 365 - Parabolic and circular mirror for catacauteiy 477 - Parallel mirrors 475 — Pascal's law 339 — Pasteboard models, showing the ring system 563 - Pendulum dynmeter. . . .1072 - Pendulum frame 294 - Photometer screen .... 474 - Precision gas voltameter . 942 — Precision pulleys 270 - Protractor on stand . . . 493 - Punctiform limelight . . . 473 Page Miiller, Friedr. C. G., Reduction tables for gas volumes mea- sured wet 615 - Reflection apparatus . . . 475 - Resistance spirals . . . .912 - Rods of different substances for thermal conduction ex- periments 639 - Rolling cylinder for recording the cycloidal path of the centre of gravity .... 274 - Self - correcting air thermo- meter 583 - Sheet cardboards with con- ducting wires 9<>4 - Short-circuited armature in the magnetic field .... 289 - Short-circuited rotor . . . 1004 - Simple Wheatstone bridge . 919 - Soft iron rod 789 - Specific gravity of gases . 367 - Spring balance 309 - Square conductor for Am- pere's rule 968 - Stability prism 275 — Steel rings for magnetizing. 786 — Thermo -cell 1062 - Thermocouple 1062 — Torsional force model . . . 309 — Torsional strength .... 309 — Torsion pendulum 298 - Tube expansion apparatus . 570 - Universal apparatus for the laws of mechanics .... 266 - U-shaped decomposing cell 943 - U-tube for liquids of different gravity 342 - Various materials for general purposes 220 - Vertical galvanometer . . . 875 — Voltameter 942 - Water chamber (optical eye) 523 - Water jet projectile appa- ratus 264 - Wind vane and wind wheel 282 - Winding formers 991 - Wood protractor 22* - Zinc-copper cell ..... 847 Miiller G., Ozone generating tube 1017 Miiller J., Laws of reflection. . 474 — Light-refraction apparatus . 483 Miiller - Recknagel, Hydrostatic apparatus 336 Multiple commutators 868,869,883,981 Multiplication effect 965 Multiplier demonstration . . . 968 Multiplier, model 876 — Nobili's 880 Muriatic acid tube, 613 Museum, equipment: see vol. I. Muslin net, Faraday's .... 808 Mutual induction, measuring . 935 Myopia 523 N Name index 1097 Natterer, Tubes with carbonic acid 613 Needle coherer 1051 - electric 811 — Galvanometers . . . 884, 885 - shaped thermocouple . . . 1062 - telegraph 958 Neesen, Mercury vacuum pump 397 Nernst lamp for demonstration. 995 - for galvanometer . . . 883 - for projectors: see vol. I. - with condenser, lens and wall bracket 879 - with protecting cylinder 878- — — with shade: see vol. I. — Velocity of ions !I44 See also the Subject-matter Index in vol. I. 1116 Alphabetical Name and Subject-matter Index. Page Nestler, Axial cross 1066 Nets of wire 210 Neumann, Heating apparatus (Neumann's tap) 617 - Light refraction apparatus . 484 Neutralisation heat 625 - of opposite kinds of electri- city 799 Newton, Colour disc 504 - Colour glasses 544 - Crossed prisms 500 - Reflecting telescope, model 531 - Rings, interference . 285, 543 • — Transparent colour disc . . 529 - Tube (fall tube) . . . 404, 405 Niaudet, Tuning fork clock . . 463 Nicholson, Hydrometer .... 346 Nickeled hollow balls 812 - metal sphere 548 - plane mirror 596 Nickelin wire 870 Nickel-plating 949 Nickel-steel compensating pen- dulum for standard clock . 247 Nicol Prisms 565 - Prism in brass mount . . . 559 Nicol with sharp edges .... 560 Niembller, Endosmometer . . . 365 - Mechanical demonstration of the laws of refraction . . 493 Nippoldt, Telephone bridge . . . 928 Nitrogen dioxide tube 613 Nitrosyl chloride tube 613 Nitrous oxide tube 613 Noack, Apparatus for the study of potential .... 809, 810 — Burner for monochromatic light 512 - Compensated water dilato- meter 572 - Discharge tube for resonance vibrations 838 - Explaining of Wheatstone bridge 917 - Goniometer for student's use 480 - Liquefying gases 612 - School galvanometer . . .881 — Voltaic fundamental experi- ments 839—842 - Zamboni pile 809 Nobert, Photographed grating . 549 Nobili, Colour rings 947 - Multiplier 880 Nodal lines, concentric .... 442 - point of tuning fork . . . 439 Node position of a swinging horse- hair 442 Nee, Thermopiles 1063 Nollet, Percussion apparatus . . 303 Nbrrenberg, Mica combinations . 565 - Polarisation apparatus . . . 553 - Sound interference tube . . 461 - Subjective colours .... 527 Nut. rotary 313 OisU stand 260, 265 Oberbeck, Cross pendulum . . . 297 Double pendulum 297 Object carrier 538 - holder, rotary . . . 557, 560 - micrometer 537 Objective chemical spectra. . . 513 - for solar microscopes . . . 540 open 558, 560 - reading device 890 telescope 890 Oblateness of a sphere of oil . 281 Observation tube 560, 562 Octagonal wire grating . . . .1042 Page Ocular glass micrometer .... 537 - micrometer (Fresnel's) . . . 545 - net micrometer 537 - prism for telescope .... 543 - spectroscope for telescope . 543 - with gap for demonstration goniometer 479 Odstrcil, Apparatus for Coulomb's law 809 - Pendulum electrometer 804, 812 Oerstedt, Deflection of magnet needle 949 - Piezometer 358, 359 Ohmann, Field goniometer . . . 229 Ohm for school use 913 - single 915 Ohm's Law 911—931 - hydrodynamic expla- nation 917 Ohmmeter 928 Oil-condenser with variable ca- pacity 1038 Oil-damping 891 Oil-insulated high tension trans- former 1035 Oil transformer for high tension 1031 Oil-vacuum pumps .... 390 — 397 Oldham, Coupling 315 Olszevski, Demonstration appa- ratus for generating liquid air 610 Costing, Laminated mirror . . . 504 Open mercurial pressure gauge . 369 — objective 558, 560 - pipe 428 Opera and field glasses .... 540 Ophthalmotrope 522 Oppelt, Siren disc .... 283, 420 Oppolzer, Reading machine . . 250 Opposed and unidirected currents 968 Opposite kinds of electricity neu- tralised 799 Optics 465—566 Optical apparatus, Mach's . . . 498 - Zwick's 496 - bench 497 - after F. C. G. Miiller . 473 - after Paalzow . .556 — 558 - after Weinhold .... 472 - for explaining micro- scope and telescopes . . .531 - for interference and dif- fraction experiments . . . 547 - for short wave apparatus 1041 - disc after Hartl . 488—490, XV - experiments with the gonio- meter 481 — eye 523 — fatigue 526 - illusions 528 - instruments 530 — 543 - measuring instruments . . 499 - outfits for projection lan- terns: see vol. I. - pyrometer 587 Opto-electrical experiments . . 1026 Opto-electric telegraphy .... 1053 Oral cavity, resonance .... 439 Organ pipe Mach's 433 - mouthpiece 427 Oscillating cross slot 315 - double crank 314 - movement 325 - prism 285, 504 - slot and crank 314 — steam cylinder 631 - thrust crank 314 Oscillation analysing apparatus. 837 Oscillations and vibrations shown with the stroboscopic cy- linder ' . 283 — electric 1030 — lo:>3 Page Oscillations forced 'JUT - of liquids 298 Oscillatory character of dis- charges 837, 1036 — discharges, stroboscopic analysis 526 Oscillographs 900 Oscillograph tube 897 Osmose apparatus . . . 364, 365 - of gases, shown with Kolbe's thermoscope 598 Osram metal filament glow lamps 995 Ostwald, Air bath 210 - Capillary electrometer . . . 946 - Clare standard cell .... 844 — Conductivity of electrolytes 930, 931 - Measuring wire 930 — Thermostat 930 - Vessel for conductivity meas- uring 930 Otto, Horizontal gaz engine 629, 630 Oudin, Currents of high frequency and voltage 1035 - High frequency apparatus: see special list. — Resonator 1037 Outfit for specific gravity de- terminations 237 Outfits, photographic 522 Outflow apparatus . . . 350, 351 - experiments .... 334, 354 - velocity of gases 411 Outflowing gases 408 Over-cooling of water 600 Overflow apparatus 574 - pipettes 220 — vessels 2,~>o Overlapping of the images . . . 524 Overshot water wheel . . 355, 356 Overtone apparatus 447 Oxidation-reduction cells . . . 847 Oxygen bombs see vol. I. - burners, see vol. I. — retorts, see vol. I. Ozone generating tube . . . .1017 Paalzow, Optical benches .556-^—558 — Oscillatory character of dis- charges 1036 — Volumnometer 380 Pachy trope for induction coils . 981 Pacinotti, Ring armature . 288, 987 Pacinotti-Gramme .Machine . . . 289 Paddle wheel 357 Page, Electromagnetic motor . . (.i~>7 Pair of bulbs after Violle . . . 651 — of cpils for galvanometer . 882 - of plates, Volta's 839 - of spur wheels with weights :>2!l Paladium-hydrogen apparatus . 853 Palmer, Micrometer gauge . . . -'-J3 Palmieri, Earth inductor . . . '.'7- I'.lcctrophorus 815 Pamphlet by Dr. Zwick .... 4'J7 Pan of balance 2tn, 2sil. 311, 571 Pannellings for lecture theatres etc.: see vol. I. Pantenius, < 'oherer 1 o.M Paper balances: see special list. — condenser . . . 900, 934, 1013 -r- condenser for singing arc lamp I""-* — electroscopes 799, 811 for filtring 2-_'o — membrane's 442, 4-4.'i - strip for recording pressure See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1117 Page Paper strip with baryum platino- cyanide 519 - tassel 825 - tube drying device .... 797 - wheel (wind wheel) .... 464 Papin, Digester 606 I 'arii- and diamagnetic experi- ments 977 Parabola of projectiles .... 264 Parabolic and cylindric mirror for thermal reflection .... 642 - concave mirrors . . . . . 643 — concave mirrors after Gar- basso 1042 - form of water jet 352 - governor 637 - mirror 476 - mirrors for Hertz's experi- ments 1039, 1040 Parachute, model 409 Paradox hydrostatic 341 Puraff in block 813 — engines: see vol. I. - lamp with slotted chimney 843, 878 - plate 809, 813 - prism Ki:i!l Parallactically mounted telescopes 542, 543 Parallax-free reading of deflection leaves 1029 Parallel copper wires 1034 - crank 314 - mirrors' 475 - switching of conductors . . 917 Parallelepiped (Fresnel's) . . . 556 Parallelepipedic wood blocks . . 206 Parallelogram of forces . .260 — 262 - of motions 258, 259 Parallelograms of pasteboard . . 260 Parallelogram of path 258 - Watt's 316 Paramagnetism . . . 952, 953, 954 Parasite plate 617 Parchment strips 799 Parr, Calorimeter for the calorific value determination of fuels 623 Parts, auxiliary, for work stand 201, 202 Pascal, Apparatus . . 334, 339, 340 Pascal's Law 336, 339 Pasteboard cylinder with bottom 598 - model of the Schroeder step view 525 - models, showing the ring system 563 Pastille press 615 Path of projectiles 258 - of rays in lenses 495 — 498, 531 - of rays in mirrors 477, 490—493, 497 - parallelogram of 258 Pearls of glass 220 Peaucellier, Guide 316 Pedometer 223 Pellat, Experiments on liquid pressure 340, XV Peltier Effect see also Differential thermoscope 588 — shown with Kolbe's thermoscope see Tubular receiver with rods of anti- mony and bismuth . . . 598 - Thermoelectric cross . . . 1063 - experiment . . . 1063, 1064 Pendulum, Airy's double p. . . 451 - apparatus 296, 297 - for vibration curves . . 451 - ball 283 - centrifugal 258 - clock with electric contact 621 - compensating 245 Page Pendulum discharger 811 - dynmeter 1072 - electric .... 798, 805, 811 - electro-dynamic 969- - electrometer .... 804, 812 - escapment 333 - for moment of inertia . . . 290 — Galilei's 258 - laws 260 - magnetic 796 - of brass and wood .... 266 - of variable length 266 - polygonal 293 - race 281 - stands 293, 294 — see also vol. I. - v. Waltenhofen's 952, 955, 956, 976 — Watt's 281 - with directly measurable length 294 — with dissymmetrical system of masses 282 Penetrative power of X-rays . . 986 Penn, Slide valve 633 Penseler, Action of heavy current fuses 938 - Parallelogram of motion . . 258 Pepys' Gasometer 211 Percussion apparatus . . 302, 303 - trough 302 Perforated cylinder for mirror and lens experiments 473 - cylindrical pillar ..... 531 Period of oscillations determined 1044 - of swing increased . . . .891 Periodicity, critical 297 - of a system 297 Permanent magnet string galva- nometer 892 - spectra .- 513 Permeability of heat rays with Kolbe's thermoscope . . . 596 Pernter, Psychrometer tables . . 655 Perot and Fabry, Interference plate 507 Perrin, Vacuum tube 1026 Perry and Ayrton, Double com- mutator 935 Perspective images 529 Pesograph 256 Petit, Thermal radiation appa- ratus 648 Petit and Dulong's law . . . .617 - Linear expansion . 570 - Mercury expansion 574 Petroleum baths for standard re- sistances 920, 921 PettenkoSer's Experiment . . . 410 Pettersson, Heating apparatus . 617 Pfaundler, Andrew's calorifere . 619 - Automatic induction indi- cator 971 - Current calorimeter .... 937 - Double chamber (differential) air thermometer 582 - Electricity resides on the surface 807 - Fulminating slab 828 - Heating apparatus for calori- metric experiments . . . .617 - Light-refraction apparatus . 493 - Lissajous figures 452 - Pacinotti-Gramme machine 289, 987 - Wave machine 417 Pfeffer, Endosmometer .... 365 Pt'laum, Electric harmonica . . 430 Phalanges in glass tube .... 1073 Pharmaceutical lecture table : see vol. I. - spectrum apparatus .... 508 Page Phase displacements produced . 900 - reversing plate 549 Phenomena of critical temperature 612 Philosophical preparations . . .1071 Phonautograph 456, 457 Phonautographic cylinder . . . 456 - recording 455 — 457 Phonic wheel after La Cour . . 463 Phonographs 460, 461 Phonometer 464 Phosgene tube 613 Phosphorescence .... 519, 520 - in the electric shadow . . . 1020 Phosphorescent lamp . . 1021, 1034 — paint 520 - substances 519, 520 Phosphorogenic action of radiant matter 1018 Phosphoroscope 285, 520 Phosphorous spoon 215 Photograph, connection scheme of oscillograph 900 - of the solar spectrum . . . 550 Photographed grating after Nobert 549 Photographic enlarging apparatus : see vol. I. - outfits 522 - recording apparatus for galvanometers 892 - work tables, see vol. I. Photography 520 — 522 Photometer 466 — 470 Photometer bench . 467, 470, 472 - demonstrating 497 - screen 465, 472, 474 Photometric accessories for opti- cal bench 472 - experiments 474 - pyrometer 587 Photometry board: see vol. I. Photophony 1058 — KKio Photos for projection chromo- scope 529 Phototelegraphy, Korn's .... 932 Physical apparatus, estimates 1075—1085 - for projection 1094—1096, XV - testimonials . . IX — XIV - balances 231—244 - work stand 201, 202 Picein (Walter's) .220 Piece of steatite 814 - of wire with lugs 311 - thin sheet steel 786 Piercing glass 828, 829 Piezometer and insets . . 358, 359 - inset for comparing gas tensions 603 - for the liquefaction of gases 613 Pigment mixtures ....... 528 Pile driver 332 - electrometer 840 - Volta's 840 - Zamboni's .809, 810, 840, 1029 Pillar, perforated cylindrical . .531 — - tare balance 236 Pin gearing 319 Pipes 426—433 Pipe for higher tones of tone series 445 - mouthpieces 427 - with 4 nozzles 420 Pipettes 220 Pipette for barometer tubes . . 602 - Luhme's -. . 381 Pistol, electric 825 — for determinations of mass 252 - for fall experiences .... 263 - target and stand 263 Piston rod of steam cylinder. . 637 See also the Subject-matter Index in vol. I. 1118 Alphabetical Name and Subject-matter Index. Page Piston vacuum pumps. . .386 — 394 Pitchblende 1027 Pitch prism 1042 Pitcher, magic 380 Pitot, Tube for velocity of flow 354 Plane, inclined . 257, 258, 267, 268 - mirror 478, 596 - of rotation conserved . . . 292 - parallel glass vessels . . . 528 - parallel vessel 645 - plate and hollow hemisphere 240 Planet wheels 324 Planimeter 230 Plano-convex lens 495 Plans of class rooms see vol. I. Plante, Cell 853 Plaster models for the isochro- matic wave surfaces . . .563 Plastic vision of both eyes. . . 524 Plasticity "... 308 Plastoscope (anaglyphon) . . . 529 Plateau, Equal weight figures . 360 - Flattening a sphere .... 360 - Irradiation 525 Plate condenser 811 - glass and milk glass scales 895 - prism 499 - slab, sliding body and balance pan for friction ex- periments 268 - hemisphere 354 - valve 408 Plates, capillary 364 - for adhesion experiments . 302 - for ionising experiments . . 986 - for optical illusions .... 528 - for vacuum pumps .... 400 - of alum, borax, sugar, calc- spar, agate, crown and flint glass, sal ammoniac . . . 646 - of black glass, citric acid and mica 646 - of brass 1033 - of glass 220 - of mirror glass with haft . 552 - of paraffin 809 - of quartz 646 - photographic 1074 - vibrating 442 Platform weighing machine . . 276 Platinum bowl for silver volta- meter 943 - cap with Bunsen burner 643, 645 - crucibles 218 - dish with wire triangle . . 602 - plate for copper voltameter 943 - stirrer for Beckmann's app. 615 - tetahedra 615 - wire glow light 474 wire netting 430 - worked up in furnaces . . 940 Pliicker-Fessel, Causing an in- duotion current 976 - Wave machine . . . 415, 416 Plug and sliding rheostat . . . 914 - commutator 867 Plumb bob 22!) - line 229 Plunging syphon 381 Pneumatic densimeters .... 348 - fire syringe 626 - trough 216 - troughs on lecture tables: see \-oi: i. Pocket chronometer 249 spectroscopes .... 510, 511 - voltmeter 858 Poggendorff, Balance 257 - Hohnenberger's machine 282, 292 Polarising battery 853 - Rheochord 912 - Stroboscopic disc . . 287. 1017 Pag* Poggendorif, Switch 853 Pohl, Mercury switch . . 867, 1013 Pointer galvanometer 933 — for short wave apparatus 1041 Poin 's action, electric .... 827 Poison siphons 381 Polarisation (of light) 550—556, 559, 560 Polarisation apparatus 285, 550 — 556 - for Ilartl's disc .... 490 — — for investigations on minerals and foodstuffs . . 538 - fortechnical purposes 561, 562 — battery 1000 — by magnetizing forces 953, 955, 956 — in double refracting sub- stances, model 562 — outfit for spectrometer . . 505 - polyoscope 563 — projection apparatus: see vol. I. - spectroscope 554 — tube for demonstrations . . 552 Polariscopes 561, 562 - after Savart 556 Polarised relay . . .960, 1052, 1053 Polariser-action 847 — and analyser after Mac6 de Lepinay 550 Polarising cells and batteries . . 853 Pole balance 796 - Grimsehl's 801 — magnetic 1010 - supplementary parts .1011 - determining cell " 1012 - finders 858 - finding paper 858 - interrupters 866 Polemoscope 475 Polished plane mirror 878 Polychord 441 Polygonal pendulum 293 Polymeter, Lambrecht's .... 653 Polyoscope 563 Polyprism 500 — Grimsehl's 494 Polytrope 292 Poncelet, Dynamometer (spring balance) ....'.... 310 — Wheel 356 Ponderomotive effect 1012 Porcelain crucibles 217 j - dishes 217 - rod and ebonite rod . . . 810 Porosity of solids 403 Porous bodies 364 - partition walls 410 Porro, Mirror arrangement . . . 475 — Prism combination .... 503 Portable apparatus for wireless telegraphy 1048 - bridge 927 - electric measuring instru- ments ...... .908 — 911 — electrometer 801 — j electroscope 1028 - experimental switchboards. Bee vol. I. — gallows 2ix; - indicator for resistance ther- mometers 586 - iron table for photometer bench 470 - lecture tables: see vol. I. - moving coil galvanometer SM. ss.-, resistance testing set . . . 112(1 stand for steel cylinders . . 609 - stink-cupboards; see vol. I. Pol trait sand busts of famous chemists. physicists etc., see vol. I. P«g« Position of nodes of a horse-hair 442 Poske, Compensated water dilato- meter f>72 - Tangent galvanometer . . . sTI Potassium bichromate *.">:; — cell Ki2i> Potential difference and potential drop 803, 826, 839 Potential drop in the neighbour- hood of a conductor . . . 810 — electric 809, 810 Potentiometer !I27 Pouillet, Compression apparatus 4 117 — Pyrheliometer i>;>2 — Sine and tangent galvano- meter 873 — Thermocouple 1061 Poulsen, Telephonograph . . . .lor, 7 Powder electroscopic Iu2."> — jars 2IS - spray 443 Power, carrying, of a magnet . 788 — • gas (gasoline) generators: see vol. I. — shunt 893 — tickle 266, 271 - transmission 997 — 999 Prandtl, Angular changes at the edges of a body by shearing stresses 307 — Rotating disc and weighted bar 290 Precession, equinoctial .... 661 Precious stone copies . '. 1066, 10117 Precision balances . . . .233 — 2.'iti — bridges 924, 925 — capillary electrometer . . . 946 — compass 792, 911 — condensers 933, !K!4 — hot wire ammeter . . . . !)lo - instruments iioii - instruments, dead beat 908, 909 — milliammeters 908 — moving coil galvanometer . ssf> - pulleys 270 — rheostats .... 921, 922, 930 - spectrometer 505 — stopcock 2o7 - telephone 1054, lo.y.i — weights 241 — 244 — work stand 202 Preface Ill Preliminary pumps . 390, 394, 399 Preparation cupboards: see vol. I. - cylinders 217 - room and Workshop equip- ment: see vol. I. — stand (microscope) .... 5. '17 — table: see vol. I. Preparations for polarisation phe- nomena . . 553, 554, 564 — 566 - for spectrum experiments . 517 - of quartz 5tl(i - pressed and impressed . 312. ."idii — radioactive 1026, 11127 Presbyopia 523 Pi-ess contact with terminals . SliT - for rale-spar doublets . . . 312 - for corks 2111 — for glass :.:>!». 5H-I — • for liquel'vinu nascs .... tins - for mercury 215. :f!ic.' - for pa~t illes lil."> for producing sliding sur- faces . . .Mill hydraulic. . 337, 338, 334, XV - with port rail pattern . . . 826 and impressed prepara- tions 312, 566 change 419 - in bent or constricted tubes 354 See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1119 Page Pressure critical 601 — diminution cools gas . . . 591 - drop in tubes 334 - flask. Schneider's 366 - gauges 368, 369 - gauge for valve regulation . 610 - governor 624 - increase coefficient .... 575 increases downwards 338, 339, XV - level 368, 419 - of the air 403 - propagation 335 - of gases 368 - regulator 426 - terminals 865, 866 - tubes for piezometers . . . 359 - tube with piston and plugs 335 PriniM- v conductor after Zehnder 1042 Prism apparatus 502 Prismatic rule 221 - troughs 516 Prism, disc and cylinder of card- board 474 - double refracting 560, 565, 566 - for carbon disulphide . . . 501 - for stability 275 - of glass 499, 500 - of rock salt 646 - oscillating 285 - reflecting 475 - stands 500 systems . . ' 502, 503 with cut in the form of a vase 494 with its hollow mould . . . 312 Producing ice by evaporation . 607 Progression, continuous, of tones 439, 445 Projectile apparatus . . . .262 — 264 - diagraph 264 - parabola 263, 264 - path 258 - pistol 263 Projection-anorthoscope .... 526 - apparatus and accessories: see vol. I. - cell 846 - chromoscope 529 - device for Foucault's pen- dulum 298 - grade scale for aluminium electrometer 802, 812 Ualcidoscope 476 lens for interference images 490 - microscope 560 See also vol. I. - moving coil galvanometer . 886 - oculars 892 - polarisation apparatus . 552, 553 - screen with stand 465 screens : see vol. I, also vol. II p. III. — stroboscope 526 - theory of mechanics. . . . 260 - thermometers 577 - voltameter !(41 - water dilatometer 572 - wave machines . . . . 41"), 41(1 Pro .>. Cation of heat . . . .638 — 648 - of light 465 — 474 - of pressure :)34 - of pressure in liquids . . . 335 - of pressure of gases .... 368 - of sound .... 405, 418. 41il Propeller 409 - of airship 357 Properties of gases 365 Protecting case for critical tem- perature apparatus . . . .612 - for galvanometer . . . 883 — for phototelegraphic apparatus . . 933 Page Protecting case for quadrant electrometers 842 — screen for observing melting process 939 Protractor on stand .... 229, 493 Pseudoscopic vision 524 Psychrograph 655 Psychrometer 654 — 656 — tables 655 Puccianti, Apparatus for repelling air bubbles 838 Pulley blocks 266 Pulley drive 328 Pulleys 265 - on cramps 266 - precision 270 Pulse hammer 606 Puluj, Fall tube 405 - Lamp 1021 - Mechanical equivalent of heat 285, 286, 627 - Radiant electrode matter . 1020 Pulverising dishes 215 - tube of glass 408 Pump-models 383 — 385 Pumps, air, 386 — 399, see also vol. I. Punctiform limelight 473 Pycnometer 250, 349 Pyramidal rectangular prism . . 503 Pyrheliometer 652 Pyro-electric apparatus .... 838 Pyrometer 584—587 - calorimetric 587 - for expansion experiments 568, 569 — (Le Chatelier's), electric . . 584 - optical, after Wanner . . . 587 Pyrometric cones 587 Pyrophone 430 Pythagorean theorem 1064 Q Quadrant 483 - electrometer . . 828, 841 — 843 Quadrants for weighing patterns of yarn, paper etc., see special list. Quadrilateral crank gear . . . .314 Quadruple inclined plane . . . 257 - quartz plate 566 Quantity and velocity of outflow 351 Quarter wave gypsum and mica plates 565 Quartz fibre electrometer . . .841 - fibres 843, 883 - lenses 519, 566, 1053 - plate, right and left rotating 560 — plates 646 - preparations 566 Quick-break lever switches. . . 866 Quincke, Oscillations, stroboscopic demonstration .... 283, 417 - Sound interference tube . .461 - Stroboscopic cylinder . 283, 417 - Velocity of sound 434 R Rabe, Turbine for Parr calori- meter 623 Rabs, Burner 208 Rack and pinion 319 - motion, guided plate with groove 324 - with spur wheel motion. . 320 Radial turbines 357 Radiant heat experiments (with Looser's thermoscope) . . 591 - matter experiments . 1018 — 1022 Page Radiation calorimeters 620 — thermal 639 — tube 642 — thermometer 651 Radiator, Righi's 1052 Radioactive preparations . . . 1027 Radioactivity 1026—1029 Radiometer, electric . . 1020, 1021 Radiometers 649 Radiophone 649 Radiophonic apparatus .... 649 Radio-telegraphy . . . .1046 — 1053 Radium bromide 1026 - cell 1026 Radius of curvature 498 Ragona Scina, Contrasted colours 527 Rail apparatus (Roller's) . 253, 258 Rails for inserting in floor of lec- ture room: see vol. I. Railway, centrifugal 276 - electric 998 Rainbow, explanation 488 Rainbow generating 503 Rain gauges 656, 657 Raising the sluices 358 Ram hydraulic 353, 354 Ramsden, Dynameter for tele- scopes 543 - Electric machine . . . . . 816 Rapid balance, German . . . .241 Rapidfolien 1074 Rapidly annealed glasses 490, 560, 564 Ratchet gears 326 Ratio of velocity of light in air, water and glass 465 Rays of electric power . . . .1039 Reaction apparatus .... 352, 353 - cannon 262 - float 352 - pressure 352, 353 - vessel for Parr calorimeter. 623 - wheel . . . 353, 404, 407, XV - wheel, acoustic 464 - wheel for steam 603 Reading devices for mirror in- struments 893 — 896 - device for thermometer . . 227 — glass 250 - machines for diagrams. 249, 250 - microscope 226 - for dividing engine . . 227 - telescopes 225, 890 - telescopes for electrometer . 1029 - telescopes for mirror instru- ments 893 — 896 Reagent stands with reagent bottles 219 Reagents for spectrum experi- ments 617 Rebenstorff, Aluminium dish. . 602 - Base for measuring glasses. 217 - Capillary ascension . . . .361 - Conservation of sound . . 419 - Colour thermoscope .... 600 — Compensated water dilato- meter 572 - Displacing -apparatus . . . 345 - Drawn brass tube ."><;<> - Experiments with air balloons 367 - Heat supply for radiant heat 649 - Influence of direction of grain on thermal conduction 639, 640 - Metallic bodies for deter- mining specific heat and proving Dulong and Petit's law 617 - Parabolic and cylindrical mir- ror 476, 642 - Radiation tube 642 - Radiometer 649 — Sensitive flames ... .419 See also the Subject-matter Index in vol. I. 1120 Alphabetical Name and Subject-matter Index. Page Rebenstorff, Surface tension 361,362 - Thermal conduction and con- vection 642 - Thermal conduction in metal rods 638 - Thermal supply for radiant heat 642 - Thermoscopic coloured sheets 600, 642 - Vertical rule 222 — Voltameter 941 - weighted flask with gauze seal 339 - Wire spiral with ebonite handle 808 - -Grimsehl, Compensated wa- ter dilatometer 572 Receivers for air pumps . . . .401 - for Kolbe's thermoscope . 596 - for retorts 219 — with carbon rods 406 - with lateral ear piece . . . 1054 - with metal rods 599 Receiving cylinders 216 - station for wireless tele- graphy 1053 Reciprocating motion 324 Recknagel-Miiller, Hydrostatic apparatus 336 Recoil of a system of masses . 261 Re-combining the resolved light 528 Recorder (storm) 659 Recording apparatus for galvano- meters 892 - drums 456, 457 - galvanometer for resistance thermometer 586 - hygrometer 654 - mercurial barometer . . . 377 - pressure gauge -369 — psychrometer 656 - rain gauge 657 - the parallelograms of motion 259 — tuning fork. . . 440, 455 — 457 - water gauge 658 Rectangle of tubes 1034 — thermo-electric 1061 Rectangular cross sprocket chain 316 — glass box 484, 485 - platinum wire glow light. . 474 - prisms of plate glass . . . 494 - rock salt prism 596 Rectifiers for charging accumu- lators with alternating or three-phase current .862 — 865 - for direct current, see vol. I. - mercury vapor, see vol. I. Rectilinear face toothing . . . 319 - propagation of light . . . 465 Reduction oxidation cell . . . 847 - tables for gas volumes, meas- ured wet 615 Reed Pipes .... 429, 450, 464 References as to darkening de- vices, see vol. I. - as to equipments, see vol. I. - as to projection lanterns and skiopticii. see vol. I. Reflecting galvanometers .877 — 884 - goniometer 481, 482 — moving coil galvanometer . 887 - prisms 475 - stephauoscope 550 - telescope, model 531 Reflection apparatus . . . 474, 475 — of heat 645 — of heat in vacuo 406 - of light 474—483 - of sound (with Kolbe's ther- moscope) 598 - of thermal rays (experiments with Kolbe's thermoscope) 596 Page Reflection, see also refraction and total reflection . . . 483 Reflectometer 499 Reflector for solar rays .... 488 Refraction of heat 645 - of light .... 479, 483—499 — see also double re- fraction 562 - of sound 419 Refractive indices .... 479, 486 Refrigerator after Carre .... 608 Regelation of ice 601 Regnault, Air thermometer. . .581 - Calorimeter . . 618, 619, 621 - Expansibility of saturated steam 604 - Expansion of gases .... 575 - Gas calorimeter 621 - Heating apparatus for calori- metric experiments . . . 617 - Hygrometer 652 - Piezometer 359 - Standard barometer .... 372 - Volumnometer 380 Dalton, Tension of steam. 602 - -Leduc, Differential baro- meter 370 Watt, Tension of water vapour 604 Regulating cock 207 - resistance for turbine inter- rupters 984 Regulator clock 246 - double switch contact, see vol. I. - for the wind pressure . . . 426 - model 277 Reichenbach, Pitot's tube . . . 354 Reichert, Gas regulator .... 207 — Ice calorimeter 617 - Injector (steam jet pump) . 408 - Rotating mirror 284 Reimann, Hydrometer .... 237 Reis, Telephone 460, 1054 Relative resistance 913 Relays 960, 961 Relay for dynaphor 860 - polarised 1052, 1053 Release, automatic 959 - electromagnetic, for fall ma- chines 254 Releasing device for Woltman's mill 355 Rendtorff's Acceleration appara- tus 257 Repeating spectrometer .... 506 - theodolite 533 Repelling air bubbles by electri- city 838 - of electricity 828 Replenisher 842 Reprints of coins, medals . . . 948 Repulsion, acoustic 463 - apparatus 407 - capillary 360 - of wave motions 413 Residing of electricity on the sur- face 807, 808 Residuum, formation 336 Resistance coils 913 - comparison with Kolbe's ma- nometer 599 - experiments 911 - of a body to the reception of motion 251 - of electrolytes . . . .928—933 plug 886 - thermometer ~>x~> - to breaking strain .... 3IK> - vessels for electrolytes 930. H31 Resistances 911—913 experimental, see also vol. I. Page Resistances for shunt experi- ments 912 - sliding 869, 870, XV Resonance apparatus 300 — coils 1037 — electric 838 - experiment, Hopkin's . . . 442 — — Lodge's 103.1 - generating current of high frequency and voltage . . 1(»3."> - mechanical -2!I7 — of electric waves 1037 - of oral cavity 439 - phenomena 443 - hertzian I ( 1 1 ."> - top 299 - tube 449, 1039 Resonator 44!>. 4.~>o - after Oudin 1037 - and tuning fork 4:!'J - floating 464 - with 4 apertures 4(14 Resultant of 2 directions . . . -_v.s Retardation of freezing .... IK is — freezing, see water hammer <>ui; Retarding ebullition . . . .(id,"). r>ui> Retort holder 203, 368 Retorts 219 - for generating oxygen, see vol. I. Reusch, Mica combination . . . ,~>ii,"i - Light refraction apparatus 493 - Press 312, .-.lit; Reversal of sodium and strontium line 517. .".is Reverse gear for locomotives. . 633 - motion excentric 318 Reversing gear with bevil wheels :$•.>."> - with spur wheels . . . 324 - pendulum 2!(5 - prisms 475 — switch 1000 Revolving device for carbons . 5 I '•'> - nose-pieces for solar micro- scopes VI 1 1 - stereoscope apparatus . . . .>_'4 Rheochords !"!•_' Rheostat after Wheatstone . . I'll' — for high tension !li>4 - Kolbe's 913 Richter, Model of a gas engine ii-_':i Rider, Slide valve cylinder . . li.'t--' Riders of aluminium wire . . . 441 Riess, Discharge M.'i-l - Distributing apparatus . . si>."i - Electric air thermometer . 829 - Inductive effect of discharge shock vj<) - Spark micrometer . . . . s:!4 Righi Radiator in.vj Right and left rotating quartz plate .".(in Rincing tables, see vol. I. Ring armature 987 — 991 - governor 637 - micrometer for telescopes . 543 - Pacim.tti's . -JSs — system of crystals •"><>:> - with hook L'S-J - with pendulum suspension . 1009 Rings for magnetizing . . . . 7sr> — for showing the flattening of the earth '-'SI Rijke.'s experiment 430 Rischbieth's (ias burette .... --'<> Ritchie, Demonstration photo- meter 467 - Electromagnetic and electric motors 957, 9.">s - Emissive and absorptive power of heat 647 — Photometers 467. «is See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1121 Page Ritchie, Top 957 De la Rive, Floating current . 968 - Rotation of electric luminous flux 1017 Rivetting model 306 Roberval, \\Yi»h bridge .... 276 Robinson, Anemometer .... 658 l!ock crystal 560 - prisms 500 - slab 596, 597 Rock salt lenses 646 - prisms 596, 646 — slabs 646 Rocker, Trevelyan's .... 420, 627 Rod-shaped thermocouple . . .1061 Rod with hook 282 Rods of different materials for thermal conduction experi- ments 639 Roget's Spiral 969 Roller, double electrostatic. . . 827 Rollers on cramps 260 Rolling cylinder 274 Roman balance 276 Rombohedra of calc-spar . . . 566 Rontgen-ray equipments for me- dical use see special list. Rontgen ray induction coils 978 — 982 -rays, school experiments . 1073 - show case 1074 Rope wave apparatus 414 Rosenberg, Angle of incident light and body colour .... 528 - Glass cube 494 - Mixing coloured rays and material colours . . . . . 528 - Oscillatory motions .... 414 - Producing smoke eddies . . 658 - Reflection apparatus . . . 475 - Theory of cyclones, trade winds 286, 658 - Universal optical apparatus 491 Rosetti, Fulminating plate . . . 835 Rostovzeff, Reflection of sound waves 598 Rotary bar 646 - with divided circle for Kolbe's thermoscope . . . 596 - converters, see vol. I. - field motor, electrostatic . 827 - high vacuum pump .... 397 - mercury high vacuum pump 398, 399 - mirror 484 - nut 313 - object holder .... 557, 560 - oil vacuum pumps . .394 — 397 - reagent stand 219 — solenoid 968 - star chart 662 Rotating bah 1009 - Heron's 407, 630 - copper disc 952,1009 - device for Geissler tubes. . 286 - disc and weighted bar, Prandtl's 290 - double crank 314 - field experiments 1001 - Geissler tubes 1017 - iron disc with copper ring . 1009 - magnet with copper disc 287, 977 masses equalised 262 - mirrors .... 284, 431, 898 - of electric luminous flux .1017 - slot and crank 315 - sphere, Heron's . . . 407, 630 - thermocouple . . . 289, 1062 [{citation of a magnet under the influence of a current . . 970 - of a movable current . . . 970 - of liquid conductors . . .971 - of magnetism 287, 977 Page Rotation of plane of polarisation 551 - of plane of polarisation by magnetising forces 953, 955, 956 - plane conserved 292 Rotations combined 292 — composed 259 Round paper membrane . . . 442 - pattern barometers .... 376 - electric instruments 906 — 908 - telephone 1054 - with antiphone . . 935 - soft iron bars 788 — spirit level 335 Rousseau, Photometer .... 469 Rowland, Diffraction gratings and copies of same 549 - Photographs of the solar spectrum 550 - Water battery 841 Rubber bag 212 - balloon with stopcock . . 403 — bellows 838 - bladder 406 — contracting by heat . . . 571 - cords 414 — discs 401 - with handles 302 - slab 822 - stoppers .... 216, 624, 1029 - tubing 207, 624 - for air pumps . . . .401 — vessel 338 Rubens, Linear thermopile . . 647 - Thermocouple to be used as wave detector 1052 - and Dubois, Astatic mirror galvanometer 883 Du Bois, iron clad galvano- meter 884 Rudberg's Boiling tube .... 581 Riihlmann, Expansion of gases at constant pressure .... 574 - Pacinotti's ring 288 Rulimer, Oscillograph tube. . . 897 Ruhmkorff, Commutators . . . 866 - Large electromagnet. . . . 954 Ruler 221 - for blackboard, see vol. I. Rules, Millimetre and metre 221, 222 Rumford, Demonstration calori- meter 623 - Demonstration photometer 467 - Dilatation thermometer . . 588 - Photometers 467 - Thermal radiation apparatus 648 - Thermometer in vacuo . . 645 Rung 330 Russner, Horizontal component of terrestrial magnetism . . 796 - Magnetic pendulum .... 796 Rutherford, Prism 503 s Sacerdote, Cohesion and adhesion tube 361, 405 Safety funnels 219 - lamp 640 - tubes 219 - valve 409 Sail cloth blinds, see vol. I. Sal ammoniac 853 - -ammoniac vapour appa- ratus . 465 Salcher, Circular motion diagraph 260 - Magnetometer 793 - Projectile diagraph .... 264 Sale conditions IV Salt for electrolytic rectifiers . 864 Salt solution vapour tension . . 602 Salts for spectrum experiments. 517 Page Samojloff, Stroboscopic disc . . 432 Sand baths 211 - influence machine . . . .816 Saturated steam 602 Saturation apparatus 957 Saturn's ring apparatus . . . . 281 - tree 944 Saussure, Capillary hygrometer 653 - Electroscope for atmospheric electricity 836 Savart, Polariscope 556 - Resonance apparatus . . . 443 — Toothed wheels . . . 283, 420 Say, Stereometer 380 Scale, female, for dividing engine 228 - for electrometer reading . . 843 Scales for galvanometers 879, 880, 895 - see also vol. I. p. 22 Schiit'fer, Overflow apparatus . 574 Schafiers, Apparatus for experi- ments with gases and va- pours 365 van Schaik, Resonance top . . 299 - Wave apparatus 412 Scheibler, Dessiccator 219 Scheiner, Accommodation of the eye 524 Schellen, Float apparatus . . . 344 Schiff, Calorimeter 621 Schleiermacher, Apparatus for the laws of centrifugal force . 277 Schlick, Ship oscillations . . . 297 — Top 292 Schmidt, Dielectric constant of crystals 1045 - Electrometer for radioactive measurements 1029 - Top .291 Schmitz's Drying tubes .... 219 Schneider, Experiments with gases 366 Schoentjes, Baroscope 367 - Specific heat apparatus . . 616 Scholars' laboratory, see vol. I. — stand camera 521 - work room, see vol. I. - tables, see vol. I. School accumulator batteries 855 — 857 - barometers 372, 373 — clocks 247 - experiments with Rontgen- rays 1073, 1074 — galvanometer . 876, 880, 881 - magnetometer 794 - pattern Wheatstone bridge. 918 - projection apparatus, see vol.1. - rheostat, Kolbe's ..... 914 — rheostats of manganin . . . 924 - spectroscope 510 — spectrum apparatus .... 508 - telegraph 959 — telescope 542 Schreibsr, Storm Recorder . . . 659 Schroeder, Step view 525 Schubert, Centrifugal psychro- meter 655 - Flat ring 990 — Hummel, ammeter .... 905 Schultze, Carriage with movable rollers 251 Schulz, Glass block 516 Schulze, Demonstration baro- meter 372 - Syphon apparatus 381 Schumann, Electrothermic appa- ratus 1064 Schwedofi, Demonstration balance 240 - Sine electrometer 804 Schwerd, Disc with apertures for diffraction phenomena . . 547 Scott, Phonautograph . . . 456, 457 Scotti, Principle of hot wire in- struments 904 See also the Subject-matter Index in vol. I. 71 1122 Alphabetical Name and Subject-matter Index. Page Screen action 808 — fluorescing 986,1073 — for mirror and lens images 473 — for projection see vol. I; vol. II p. XV. - of Bristol board 285 — of sheet zinc 1042 - with clamp 900 — with ground glass disc, for interference experiments . 545 — with rotary disc 646 Screening effect 812 Screw apparatus 273 — flyer 409 — jack 313 — line, formation 273 — micrometer 225 — motion for coils 882 — press 314 — spindle, rotary 313 — thread with ratchet brace . 314 — toothing 322, 323 — winding gear 330 — with right and left-handed thread 313 — with 2 threads 314 Sealing wax and sulphur rod etc. 797, 798 Secondary cells 853 — clock 248 — conductor (Zehnder's) . . . 1043 Seconds contact for standard clock 247 — pendulum 246 — watch 244 Section of a cylinder with 2 equilibrium positions . . . 345 Sections of telegraph cables . . 962 Sectional model of the steam- cylinder 631—633 — models of valves . . . 408, 409 — models of water meters . . 355 Seddig, Lines of force 830 Seebeck, Thermo-electric appa- ratus 1061 Seger, Cones for pyrometric meas- urements 587 Segner, Reaction wheel see Bar- ker's mill 353 — Water wheel 334 Seibt, Resonance of electric waves!037 Selenium cells . . 933, 1060, 1061 Self-correcting air thermometer. 583 — -exciting influence machine 817, 1072 — induction coil. . . . 1057, 1058 - induction, measuring . . . 935 — — proved 976 - standards 976 — — variable 1037 Semi-cylindrically bent plates . 617 - -cylindrical double screen . 596 — — receiver for Kolbe's ther- moscope 596 Senarmont, Polariscope .... 556 — Prism 565 — Thermal conduction in crystals 639 Sensitive flames 418, 419 — thermoscopic sound .... 600 Sensitivity of ear to sound . . 439 — of selenium 1060, 1061 Separate windings for galvano- meter 891 Separating funnels 219 Series of tuning forks 445 — resistance 1010, XV - for arc lamps. . 1057, 1058 - resistances for experiments with Kolbe's thermoscope 598 — — for galvanometers . . 885 — — for voltmeters .... 909 Page Series resistance subdivided . . 904 — rheostats, precision . .921, 922 — wound motors .... 997, 998 Set of accessories for microscopy 538 - of glass plates 551 — of hooked weights . . . .261 - of preparations for polari- sation experiments . . .553 — of resistances 913 — of Tesla apparatus .... 1034 — of weights 236, 241—244, 304, 481, 623 Set of weights with hooks . . 266 Sextant 482, 483 Sextuple manometer after Kolbe 599 Shadows, coloured 527 Shaking and rubbing tubes . . 830 — device for coherer 1052 Sharpener for cork borers . . . 216 Shearing stress 306 - stresses occurring in pairs . 307 Sheet brass hollow cylinder . . 809 — iron cone 408 — — cube 810 — — cylinder with holes . . 338 — — electrodes 514 — — flasks 596 — — hollow sphere 806 — — pendulum 296 - strip for elastic limit, viscosity and strength . .311 — — tube 809 - metal pieces 802, 812 Shell type transformer .... 1008 Shielding box against explosions see vol. I. Ship oscillations 297 Ship's capstan 330 - compass 792 — screw 357 — siren 423 Shoe guide 312 — with writing point for tuning fork 440 Shore turning cranes 331 Short-circuited armature in the magnetic field 289 — — rotor in the rotary mag- netic field 1004 — triangular beam balance . 232 — waves 1041 Show cases, see vol. I. Shower of mercury 403 Shunt dynamo 992—994 — dynamos see also vol. I. — for galvanometer . . .883 — 885 — for hot wire ammeter . . . 910 - for mirror galvanometers . 893 — for reflecting galvanometers 879 — for sine and tangent galvano- meter 873 - plug 886 — resistances for experimental work, see vol. I. — — with interpolation . . 920 - universal 888 — wound motor .... 997, 998 Shunting forceps 916 — small potential-differences .1013 Shutter hetiostat, see vol. I. Siemens Armature .... 988, 990 — Ozone generating tube . .1017 — Sine and tangent galvano- meter 873 — Unit 913 - Water pyrometer 587 Sieve annex for Bunsen burners 208 — of the Vestals 380 Sieveking, Fontactoscope . . . .1029 Sifter for iron powder .... 789 Signalling device for resistance thermometers 586 Page Sike, Hydrometer 347 Silbermann, Compression pump 407 — Hollow prism 491 - Refraction and reflection . 487 - and Pavre, Calorimeter for determining the heat of com- bustion 623 - Compression and expan- sion of air 626 — — — Mercury calorimeter lil'i Silver coin with pyramid mirror 952 - -plated copper plate for Mo- ser's breath figures. . . . 410 — voltameter 943 Silvered and blackened glass flasks 644 Silvering apparatus 949 Simple machines 313 Simplified absolute electrometer 811 Simultaneous colour contrast . ~i-~ Sine and tangent galvanometers 872, 873 — electrometer 804 — vibration 299 Singing arc lamp 1058 — flames 430 — membrane 1009 — water hammer 606 Single arm balance 23(1 — constituents of air-balloon apparatus 367, 368 — ohm 915 — phase alternating current rec- tifier 862—865 — -tooth wheel and star wheel 326 Sinks (for laboratory) see vol. I. Siphon with marking rings . .281 Sire, Archimedian principle . . 343 - Hydrostatic paradox . . .341 - Polytrope 292 — Rotational motion can gene- rate successive motion . . 282 Siren discs 283, 420 Sirens 420—423 Six, Thermo metrograph . . . .579 Skeletons of men and animals .1071 Skioptica see vol. I. Skutsch, Model of Schlick's top 292 Slab for the parallelogram of motions 258 - with pair of pulleys . . . 4!i."i Slaby-Arco, Wireless telegraphy lo.">i> Slide induction apparatus . . . 975 — -rest lathe see vol. I. — — microtome 538 — rule 230 — wire bridges 918, 919 — resistance 915 Slider for measuring bridges . . 926 — stage and aluminium bush 794 Sliding and plug rheostat . . . 914 — body, plate glass slab and balance pan for friction experiments 268 — friction .... 268, 301, 302 — resistances 869, 870, 944, 998, 1073, XV — — see also vol. I. — resistance for dynamo models 988 — resistances in vertical ar- rangement Iu7:i Slit annex for Bunsen burner . 208 Slot and crank 314, :m — excentric 317 Sluice raising apparatus . . . 358 Small arc lamp £ — colour bottles 539 - disc with rotary suspension 429 - electric motors !>!>7 — flask and watch glass . . . .''>!."> - flasks with absorbent liquids 516 — flat flask for showing the durk rays 644 See also the Subject-matter Index in vol. I. Alphabetical Name and Sub:ect-matter Index. 1123 Page Small glass tube with platinum lugs 512 - jjvpsum plate 565 - house and its perspective image 529 - induction coils 982 - coil for Thomson's ex- periment 1058 - metal frame for soap solution 543 - mirror and total reflecting prism 531 - thermograph 579 - thermometers 577 - tripod with vessel for sucking an egg 403 - tube with mercury .... 494 - tuning forks 436 - Weinhold optical bench . .531 - window 560 - wood board 1025 Smee Cell 849 Smelting crucibles 218 Smoke condenser 827 - eddies 658 — — see vol. I. Soap bubble apparatus .... 812 Soda caustic 849 Sodium bichromate 853 — cell 1026 - lamp 562 - line, reversal 517, 518 - sulphate solution, supersatu- rated 364 - tube 518 Soffit curtain see vol. I. Soft iron rod 789 Solar microscopes .... 539, 540 - prism, Herschel's 543 - radiation thermometer . . 651 — spectrum 518 - photographs 550 Soleil, Compensator 556 - Wedge compensation . . . 560 Solenoid on stand, for using with Hartl's balance 240 - with pointer 968 Solid air generated . . . . 610, 612 - oxygen 612 — and hollow cylinder for the Archimedian law . . . .343 - half cylinder . . . 274 - semi-circle .... 274 — ozone 612 Solution, supersaturated .... 364 Sondhaus' Lens 419 Sorting balance 241 - balances for yarns and pat- terns see special list. Sound analysis apparatus . . . 459 - figure disc 442 - interference tube . . . 461, 462 - propagation 405, 418 — • radiometer 464 - refraction 419 - thermoscopic 600 - velocity 434 - vibrations imitated . . 415, 417 Sounders, fixed . . . 809, 810, XV Sources of galvanic current 839 — 865 Spare carbon plates 852 - cartridge for Parr calorimeter 623 - cupric oxide plate .... 849 - electrodes for electrolytic rec- tifiers 864 — glass vessel 852 — glow lamp 878 - magnesium tape 522 - mercury arc lamp 515 - parts for influence machines 823, 824 - selenium cell 933 - wick tube for Hefner lamp 472 - zinc plate 849, 852 Page Spark chronograph .... 248, 463 - discharges, stroboscopic ana- lysis 526 - micrometer . 811, 834, 1031, 1038 — tubes 514 — for metal spectra . . . 514 Sparking pillars 980, 985 Spatial vision 524 Spatulas 215 Speaking arc lamp . . . 1057, 1058 Special optical outfit for mega- diascope XV Specific gravity balance . . 233, 237 — — determinations, outfit for 237 - (displacing method) . . 250 - indicators .... 346, 347 - of air ...'.,.. 402, 576 — — of gases 367 - tester 857 — heat 616—622 -1— experiments with Kol- be's thermoscope 597 — — — with Looser's ther- moscope 590 — — of gases 626 — resistance 911 — difference 936 Specimens, microscopical. . 538, 540 Spectra of incandescent vapours 512—515 — tables 518 Spectrograph 508 Spectrometers 505, 506 Spectrophotometer.'see ocular with gap 479 Spectroscope 509 — 511 — for telescope 543 — see also reflecting goniometer 482 Spectrum analysis 499 — 518 - apparatus .. . . 481, 505 — 511 - see also demonstration goniometer 479 - demonstration . . . .499 — 504 - lamp demonstration table see vol. I. - lamps 512 — 515 - phenomena 556, 560 — projection see vol. I. - tube 509, 515 — — stand with condenser and electromagnet .... 509 Speed counter 999 Sphere of glycerine clay . . .281 — plane and arched plate for equilibrium experiments 274 — with ring 567 Spherical and chromatic aber- ration 495 - concave mirrors. . . . 596, 643 — condenser 811 — flask for concentrating dark rays 644 - mirrors 477, 478 — resonators 450 — tubes 220 Spherometers 223 Spies, Explanation of Wheatstone bridge 918 - Mercury vacuum pump . . 398 Spinthariscope 1027 Spiral disc, Archimedian . . . 318 - for induction experiments . 813 - logarithmic, toothed wheels shaped according to it . . 321 — Roget's 969 - spring for showing the force- action of a weight . . . .251 - models for imitating sound vibrations .... 415 — wheel with toothed wheel . 324 - with glow lamp 1009 Spirit Bunsen burner . . - lamp - lamp, Breitenlohner 's — level — and plumb bob Page 209 209 512 335 229 - sodium lamp 562 Splintering glass vessels .... 829 Spoons 215 Spray flask 220 - for fitting over door for use in case of fire, see vol. I. Sprengel, Mercury vacuum pump 397 Spring balance . . . .286, 309, 310 - for showing centrifugal force 281 — dynamometer and carriage 258 - pendulum 297 - thermometer 651 - vacuum gauge see vol. I. Spring, Elastic limit 308 Spur wheels 318 — 321 — with screw toothing . 322 Square conductor 968 — formed of tubes 567 — glass slab 810 — paper membrane 442 — screw thread 313 Squirrelcage rotor 1004 Stability apparatus 274 - parallelepiped 275 — prism 275 Stable equilibrium .... 273, 274 — and unstable axes .... 282 Staff for measuring 223 Staged paper condenser for sing- ing arc lamp 1058 Stage for prisms 560 - for setting up prisms . . .646 - with stand, platinum spiral and spirit lamp 645 Stahlberg, Reflection apparatus 475 - Refraction apparatus . . . 493 — — box 484 Stamp, plate, mould and frame for pressing carbonic acid plates 609 Stand, Ampere's 966, 967 — and boxes for the accessories of Kolbe's thermoscope . 598 — and boxes for the accessories of Looser's thermoscope . 594 — camera 521, 522 - clamps 414, 799 - for absorption vessels etc. . 516 — for achromatic lenses . . . 495 — for barometer tubes . . .371 — for burette holders .... 203 - for clamping carbon rods . 973 - for clamping Geissler tubes. 101 7 — for concave and convex mirrors 477 — for filtering 203 — for fixing vibrating bodies 454 — (holder) for fluorescent cubes 518 — for holding glass tubes . .512 — for lenses 496 — for magnetic needles . . . 786 - for Melloni's apparatus . . 645 — for model theodolites . . . 532 — for Paalzow opt. bench . . 557 - for photometric accessories 473 - for physical work . .201, 202 - for platinum crucibles and dishes 218 - for platinum electrodes . . 947 — for prisms 500 — for reagents, with bottles . 219 - for rope wave apparatus . . 414 - for Rowland grating . . . 549 - for selenium cells . . 1060, 1061 - for school spectroscope . .510 — for spectrum tubes . . . .515 See also the Subject-matter Index in vol. I. 71* 1124 Alphabetical Name and Subject-matter Index. Page Stand for the iron har of con- traction apparatus .... 568 - for vacuum tube 1023 - for X-ray tubes 986 - Gauss' . . '. 204, 205 - heliostat see vol. I. - insulating 798, 799 - terminals 866 - -with apparatus for the laws of mechanics .... 265, 266 - with pendulums . . . 293, 294 - with stays 202 - with steel pivot 464 Standard barometer 372 - candles 472 - cells 844, 845 — clock, electric 247 - condenser 813 - copper-zinc cell 844 - ink writer 959, 1049 - metre 222 - photometer bench .... 467 - resistances 919 — 921 — rules 222 - self-induction 976 - thermometer 578 - tuning forks 436 — — — on resonance boxes 438 — fork with resonator . . 439 Standing barometer 402 Star burner attachment . . . 210 - chart 662 - -connection 1005 - spectra table 518 Starke-Wehnelt, Electrolytic inter- rupter 928 Starting and regulating resistance 997 State, change of 600 — 615 Statically indefinite forces . . . 305 Static deflection 297 - electricity 797 — 838 — momentum 269 Statics and dynamics . . .265 — 411 Stationary electric waves 1043, 1044 Station barometers .... 373, 374 - telegraph 959 Statoscope for balloons . . . .651 Steam barometer 601 — boiler 569 - Weinhold's 213 - capsule 645, 647 — engine 631 — 637 - cylinder 631 — 633 — generator for electric machine 816 - jet pump 408 - lead on lecture tables, see vol. I. - pipe ' . . 429 — piston 631 - reaction wheel .... 407, 630 - saturated and superheated. 602 — tension 602 Steatite piece 814 - see 4 rods of glass etc. 797 - with handle 797 Steel bars 444 - on resonance box . . . 434 - coherer, adjustable .... 1052 - cylinder containing com- pressed air 610 - for calorimetric experi- ments 623 - for carbonic acid . . . 609 - cylinders 444 - flasks for compressed hy- drogen and oxygen, see vol. I. - rings for magnetizing . . . 786 — ruler 222 - spheres for lines of force curves 962 - wire for glowing experiments 996 Steinbrinck, Vacuum syphon. . 360 Page Steindel, New wave machine 415, XV Steinhauser, Schemer's experi- ment 524 Steinheil. Hollow prism .... 501 Step cone transmission .... 328 Stephanoscope 550 Stephenson's Link 316 - Reverse gear for locomo- tives 633 - Thermometer screen . . . 650 Stepped gearing for laboratories . 998 - sliding resistance 870 Step view, Schroeder's .... 525 Stereometer 380 Stereoscope 524 Stereoscopic lustre 524 — views . 524 Stern, Tone *ariators 446 Stink-cupboards, see vol. I. Stirrer apparatus 947 - of platinum for Beckmann's app 615 Stirring rod 220 Stirrup, copper 1033 Stock cells 850 Stohrer, Magnetic induction machine 973 Stokes, Fluorescence spectrum . 519 - Sunshine recorder .... 652 Stool insulating 825 Stools, laboratory see vol. I. Stopcock 207 Stopcock models (vacuum pumps) 387 Stopcock vacuum pumps . 386, 387 Stopper of rubber 1029 Stoppers 216 Stop watch 244 Storing box for luminous sources 474 Storm recorder 659 Strahlende Elektrodenmaterie, pamphlet . . . 1020 Straight pile driver 332 Strain on the chord rivets . .306 Strand for resistance thermo- meter 587 Stratification of liquid masses . 573 Straubel, Mercury arc lamp . . 515 Strength, torsional 309 Striation apparatus 364 String galvanometers . . . 891, 892 — induction coil 935 Strings, vibrating 440 — 442 Strip Chronograph 249 Strips for stroboseopic cylinder 283, 525 - of parchment 799 - of steel and zinc 581 Stroboscopes . . 283, 417, 525, 526 Stroboseopic cylinder . . . 283, 417 - demonstration of a vibrating air column 433 — discs .... 283, 432, 453, 525 — tuning fork 433 Stromann, Optical demonstration apparatus 487 Strontium line, reversal . . . .518 Student's spectroscope . . . .510 — work room see vol. I. Stuffing box receiver 401 Stump!, Interval apparatus . . 447 - Triad apparatus 449 Subjective colours 527 Successive colour contrast . 526, 527 — key 868 Sucking action of chimney cowls 408 - of flwoing water . . . 354 - an egg 403 Suction phenomena of outflowing gases 408 - pump 383 - with electromagnetic motor 958 Page Sulfuric acid cryophorous . . . 608 Sulphate of copper 853 Sulphur and sealing wax rod etc. 797, 798 Sulphuretted hydrogen tube . . 613 Sulphurous acid liquefied . . . 612 - tube v. 613 Sundial 244 Sunshine recorder 652 Superficial colours 544 Superheated steam 602 Supersaturated sodium sulphate solution 364 Supplementary outfit for photo- graphy 522 Supplies for general use . .201 — 220 - for work with mercury 214, 215 Support boxes 206 Supports, wood 206 Surface bolometer 648 — goniometer 229 - law see regulator model . . 277 - measuring 230 - principle 290, 291 — tension 361, 363 Suspended board for reflecting galvanometers 879 see also vol. I. Suspension board, see vol. I. Swiss pattern thermometer . . 581 Switch apparatvis for producing phase displacements . . . 900 Switchboard, experimental see vol. I. Switchboards for accumulators 860, 861, 1073 - for charging accumulators 859 Switch contact rheostat . . 915. 916 - for chronographs 250 - for machine tools .... 326 - for singing arc lamp . . . 1058 Symmetrical double gap . . . 479 Synchronism, demonstration . . 1004 Synthesis of colours 529 - of the spectrum . . .499 — 518 - of vibration 417 Syphon 380, 381 - apparatus 381 — barometers 372, 373 - explaining 371 — fountain 404 — mercury 404 - pressure gauge 369 - vacuum 360, 361 — with rubber ball for accumu- lators 857 Szekely, Boyle's (Mariotte's) law 378 Szymanski, Earth inductor . . 972 - Electrometer 801 — • Pressure change in sound waves 419 — Lines of force theory . . . 964 - -Thomson, Mirror galvano- meter 883 Table balance 241 — draught exhaust see vol. I. — for hydrostatic balance . . 240 — - for projection lanterns, see vol. I. ... - for setting up ;ippiirjiius. . 205 - for setting up concave mir- rors 643 - of spectra 518 - terminals 865 Tachometer 999 — attachment 281 — for whirling tables .... 280 See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1125 Page Tackle 266, 271 - frame . 271 Tangent electrometer 801 - galvanometer . . . .871 — 873 — galvanometer ring for school galvanometer 877 Tangential wheel 356 Tantalus Cup 380 Tap 207 - (Neumann's), calorimetric heating apparatus . . . .617 Tape measure 223 Tare balances 236 Target, pistol and stand . . . 263 Tassel of paper 825 Taudin-Chabot, Cycloidal gear. 324 Technical balances .... 234, 235 - decade resistances .... 923 - measuring instruments . 905 — 911 - polarisation apparatus . .561 Tecln's Burner 209 Telefunken system of wireless telegraphy 1050 Telegraph cables, sections . . . 962 Telegraphy, electromagnetic . . 958 - wireless . . . 1040, 1046 — 1053 Telephone .... 460, 1054—1060 - bridge 928 - for measurements 886 - installation 1055 - receiver with antiphone 930, 935 Telephonic lecture instruments 1055 Telephonograph 1057 Telephony 1054—1060 - wireless , . 1057 Telescope 540 — 543 Telescope, demonstrating . 473, 497 - for reading galvanometers . 890 - for reading mirror instru- ments 893 - for reading . scales .... 225 • -models 531 - with scale 891 Telurion-Lunarion 662 Temperature change on expansion and contraction of gases. 626 - determining with thermo- couple 1062 - drop in solids 640 - drop in a solid, see also . . 599 - influence on resistance . .912 Tempered steel wires 788 Tenfold solenoid 968 - wire frame 968 Tensile apparatus, see monochord 441 - forces measured 310 Tension and acceleration meter 257 - model 307 - of steam 602 — 606 - of surface . . . : . .361 — 363 - of water vapour . . .601 — 606 Tensive force of vapours . . . 365 Tensive and compressive strain 269 Terminal board for galvanometers 879 Terminals 865, 866 Terquem, Burner for monochro- matic light 512 Terrestrial globe 660 - magnetism, horizontal inten- sity 796 - telescope 541 — 543 - telescope, model 531 Tesla, High frequency experi- ments 1030 — 1036 - Lamp 1034 - Three-phase motor . 1002, 1003 -Transformer with Leyden jar 1045 Test apparatus for lightning ar- rester 928 - ball 810 - on ebonite rod .... 805 Page Test card, astigmatic 522 - certificate for thermometers 585 — disc 810 - on ebonite rod .... 805 - electroscope 802, 812 - glasses 217 - glass holder 217 - stand 217 - needle 786 - pieces for calorimeter . . . 618 Tester for coherer 1049 Testimonials XI— XIV Testimonials as to Fittings, see vol. I. - re experimental switchboards, see vol. I. - re laboratory apparatus sup- plied, see vol. I. - re projection apparatus, see vol. I. Testing and calibrating thermo- meters 225 - apparatus for thermometers . 581 - condenser 935 - church bells 438 - electroscope 802, 812 - illuminating gas. Ask for quotations Tetrahedra of platinum .... 615 Thenard and Gay-Lussac, Tension of vapours ; 604 Theodolite models 532 Theodolites 532, 533 Theorem, Doppler's 435 Theory of electrons . . . 1025, 1026 - of lines of force . . .962 — 965 Thermal conduction in metal rods 638—640, 590, 596, 599 — nt liquids and gases 640—648, 597, 599 — consumption, on evapora- ting 597 - convection in liquids and gases 641, 642 - effects of electric current 936—940, 588, 593, 598 — energy and total energy . . 937 - expansion . . . 567 — 584, 589 - reflection 642, 643 - supply for radiant heat. . 642 Thermo-cell 1062 Thermocouple (electric pyro- meter) 584 - for inserting in the hydraulic press 601 - rotating 289, 1062 - (wave detector) 1052 Thermoelectric cross 1063 Thermo-electricity 787, 1061 — 1064 Thermographs 579, 651 Thermo -Hygrograph 651 - -magnetic apparatus. . . . 796 Thermometer . . 576 — 587, 930, 935 - electric 829 - for calorimeter .... 623, 624 - for low temperatures. . . . 610 - for schools 578 - for springs 651 - for standard cell 845 - in vacuo 645 - mercury resistance th. . . 937 - metastatic 615 - on stand for concave mirror experiments 643 — screen 650 - tested and calibrated . . . 225 - testing apparatus 581 Thermometrograph 579 Thermopiles for demonstrations 1062, 1063, 1074 - for generating currents 859, 860 - for optical experiments 646, 647 Page Thermo regulator 207, 208 Thermoscope 588 — 600 Thermoscope after Weinhold for showing maximum of density 573 - for radiant heat 588, 643 - (Drebbel's) 567 — (Galilei's) 567 — (Kolbe's) 595 — (Looser's) 589 - (Rebenstorff's) 600 - used as manometer .... 594 - (Weinhold's) . . .573, 588, 643 Thermoscopic coloured sheets 600, 642 - sound 600 Thermostat, Ostwald's .... 930 Thick artificial corks 597 Thierfelder, Cycloidal double rail- way 267 Thin liquid films 543 - plates and their colours 543, 544 - walled dish of sheet copper 607 Thoma, Hematometer 538 Thompson, Cone for producing a rainbow 503 - Wave machine for Hertzian waves 412 - Glan prisms 565 Thomson, Aluminium egg . . .1004 - Experiments of inductive repulsion 1008 - Double bridge 927 - Lowering of the melting point by pressure 607 - Luminous sphere 1024 - Magnetizing ring loin - Repelling action of electric field 1008—1010 - Replenishes 842 - Vacuum tube 1023 - -Kirchhoff, Electrometer balance 844 Mascart, Quadrant electro- meter 841 — Szymanski, Mirror galvano- meter 883 Weinhold, Quadrant electro- meter 842 Thorium light burners see vol. I. Thornycroft, Boiler 636 Three phase and alternating cur- rent 1000—1006 Three phase continuous current transformer, see vol. I. • -phase current dynamo 992 — 994 - model 1003 - motors 1006 - electrolytic rectifiers. . 864 — motor . . 1000, 1002, 1003 - -three-phase transformer 1008 - transformer, see also vol. I. - -port slide valve cylinder 631—633 — -way cock 207 Throwing apparatus for screw flyers 409 Thrust crank chain 316 Thrusts in a crankshaft .... 304 Thunder cloud, electric .... 827 Time is necessary for the change of condition of motion . .251 Tinder box 410 Tinfoil screen 647 Tipping device for steel cylinders 609 Tone impact apparatus . . . .461 - manometer 429 - variator 446 Tongs for crucibles 215 - for mercury 215 Tongue, anatomical model . . 1069 Tonometers . . 446 — 448 See also the Subject-matter Index in vol. I. 1126 Alphabetical Name and Subject-matter Index. Page Tonometric apparatus . . .446 — 451 Tool boards, see vol. I. - cupboards see vol. I. Tooth and worm gears . .318 — 326 Toothed gear for oscillating move- ment 325 — gearing with fly-wheel . . 313 — wheel connecting and dis- connecting device .... 326 - wheels, Savart's . . . 283, 420 — wheels with excentric axes 321 - with intermediate wheel 320 Top 251, 291 - apparatus 293 - for rotating colour discs 504, 529 - of celluloid for Bunsen cells 848 — Schlick's 292 Topler, Demonstration apparatus for statics and dynamics . 267 - Influence machine 817, 818, 1072 — Magnetic curves 962 - Manometric flame pipe . . 428 — Photometer screen .... 472 — Pressure level .... 368, 419 - Stroboscopic disc . . . 432, 526 — Hagen-Neesen, Mercury vacuum pump 397 Torricelli's experiment . .370 — 372 - law 351 Torsional elasticity .... 308, 309 — force model 309 - oscillations and moment of inertia 290 - strength 309 Torsion balance 794 - moment 270 - pendulum 298 Torso, model 1069 Total and thermal energy . . . 937 Total free magnetism is zero. . 793 - reflection in the water jet 352 — — of light 483 — 499 — reflectometer 499 Tourbillipn, electric 828 Tourmaline plates 555 — tongs 555 Towbridge, Tangent galvano- meter 873 Tower, leaning 274 — with lightning conductor . 835 T-piece for hose unions .... 207 Trade winds 658 Trajectory 263, 264 Tralles, Hydrometer 346 Transformer . . . .898,1006 — 1008 - electric, see also vol. I. - for alternating current . . 864 — for high tension (Elster and Geitel's) 1031,1032 — model 991 Transfusion 410 Transit case for fontactoscope . 1029 Translator pillar 959 Transmission of motion . .313 — 333 — of motion by belt, cord and chain 328 — of power 997 — 999 Transmitter for Hertzian waves 1041 Transparent colour discs . 504, 529 — galvanometer scale .... 880 - projection screens, see vol. I. — solar spectrum 518 Transporting and hoisting ma- chines (models) . . .328—332 Transverse strength apparatus . 304 — vibrations of rods .... 434 Transverse waves 412 — 417 Trap for mercury 215 Traverser with pit 331 Travelling and altitudinal baro- meter 374 — crane 331 Page Tree, Saturn's 944 Tremery, Astatic magnetic needle 786 Trevelyan's Rocker .... 420, 627 Triad apparatus 449 Triangles of wire 210 - on stand 274 Triangular paper membrane . . 443 - prismatic pipe 428 - screw thread 313 Tribometer 301, 302 Trick, Slide valve: see Double inlet channel slide valve . . . 633 Trieder binoculars. 540 Tripods 210 Tripod stand for barometer tubes 371 — for photographic appa- ratus 522 Trough cell 847 — for mercury 1009 - for percussion experiments. 302 — for wave motions . . . .413 - form prisms 502 - pneumatic 216 - pneumatic on lecture tables, see vol. I. Trussevitch, Kundt's manometer 419 - Reflection of sound waves. 598 Tube after Aron 1044 - after Lecher 1044 - expansion apparatus . 569, 570 — level model 335 - receivers with metal wires . 599 — sheet iron XV Tubes, electrodeless 1034 - for barometric experiments 370, 371 - for combustion 220 - for demonstrating vapour tension 604 — fork-shaped, for interference 462 - for liquids of different gravity 342 - for spectrum demonstrations 515 — for total reflection .... 494 — with carbonic acid . . . .613 - with closed pressure gauges 336 — with iodine 601 — with light and dark cross .1020 — with liquefied gases . . .613 - with pistons 426 - with stand for Hopkin's ex- periment 442 Tubing, bent 220 - of rubber 207 - of rubber for air pumps. . 401 Tubular magnet coil 1019 — receiver 598 - stand for photographic ca- meras 522 Tun, magic 380 Tuned pipe for Kundt's mano- meter 419 - pipe on stand 598 Tuning fork apparatus . .452 — 455 - chronograph . . . 248, 256 — see also spark chronograph 463 — fork clock 463 — — curves on stand . . . 455 — — exciter clamp .... 440 — forks 435—440, 456, 463, 464, 1039, XV - chronographic .... 455 - for demonstrating curves 452, 455 — for limit of audibility . 444 — for Quincke's apparatus 434 - for resonance . . 439. 443 - for resonance tube . . 449 - on resonance boxes 436, 437 — Stroboscopic 433 — with electromagnetic drive 436 - with recording device. 456 Page Tuning forks with resonators 439, 458, 4.->!i — with sliding weights 438, 439, 458 Turbine after Rabe 623 - interrupter 984 — models 356, 357 Turning cranes 331 — gear with partially toothed bevel wheels 326 - moment 304 Turntable 331 Turret clock movement . . . .333 Tweezers 215 Twin flexible 1054 Two phase alternator . . 1003, 1004 — -phase current dynamo 992 — 994 — — motor 1002, 1003 Tyndall. Contraction apparatus 568 — Cooling effect of gases . . 642 — Drum (light-refraction appa- ratus) 486 — Electrophorus 815 — Expansion of gases .... 568 - Melting of bodies in the magnetic field 953 — Model geyser 631 - Percussion trough .... 302 — Propagation of sound . . .419 — Reflection of light .... 474 - Silver coin with pyramid mirror 953 - Specific heat 616 - Temperature change on com- pression and expansion of gases 626 U Unaxial circular polarising nii<-;i combination 565 Undershot water wheel . . 355. 356 Unequal thermal conduction . . 639 Unidirected and opposed currents 968 Uniform and non-uniform motions 258 - pressure in all directions . 403 Unipolar Induction .... 288, 976 Units, electromagnetic .1010 — 1013 - of resistance 913 Universal-apparatus for astrono- mical geography 662 - apparatus for the laws of mechanics 266 — clamp 204 — clock 662 - coupling, double 317 — double socket 202 — dynamo 992—994 — - galvanometer 885 — gas burner -i>!l — gasometer -\-2 — hydrometer 347 - hydrostatic apparatus . . . 334 — kaleidophone i.il - measuring instruments. 902, 903 - mouthpiece 420 - optical apparatus . . .488 — 493 - pattern Wheatstone bridge 926 - scale holder on reading tele- scope 894 — shunt 888, 893 - slider 955, 956 — sliding resistance 870 — socket -'"-' — spring balance 310 — stand 202, 968, XV - for spectroscopes . . . ."> I i — — for spectrum experi- ments 512 - wheel apparatus 320 Unstable equilibrium . . . 273, 274 See also the Subject-matter Index in vol. I. A'phabetical Name and Sulrect-ma'ter Index. 1127 Page Uppenborn, Diffusion of liquids 364 - Induction apparatus for resis- tance determinations of electrolytes 928 I'ranite plate 517 Uranium cube 518 - glass plate 518 - metal 1027 - pitchblende 1027 Uranotrope 661 Urinary organs 1069 U-shaped absorption-box . . . 516 U-shaped decomposing cell 943, 944 U-shaped glass tube for electro- lysis 973 I' -shaped tube for heating of mercury 937 U-tubes 220 U-tubes for oscillations of liquids 298 Uviol mercury vapour lamp . .1026 Vacuum bulb 1016 — bulb with butterfly . . . .1021 - double bulb 1022 — gauges 368—370 - pumps 386—399 — — Kohl's system 390—394, 398, 399 - piston pumps . . . 386—394 - scale 1016 — -siphon 360, 361 — tube 1016, 1036 - tube after Perrin 1026 - illumination 1025 - with diamonds .... 1022 - with minerals etc. 1021, 1022 - with piece of metal sjieet!022 - with stratified light. .1025 - vibrator 1025 Valenta and Eder, Continuous va- pour spectra 512 Valve models 408, 409 - tube 1021, 1024 - as audion 1052 Vanderfliet, Flexible wire netting 811 Vane water meter 355 Vaporiser as aspirator .... 598 Vapour and gas condensation (experiments with Looser's thermoscope) 592 - apparatus for sal-ammoniac 465 - densities 613, 614 - in an air-filled space . . .601 Vapourisation heat 621 Vapours mixed with gases . . 604 - spectra, continuous . . . .512 - tension 602 Variable angle prism 502 - self-induction 1037 — tuning forks . . 438, 439, 458 Variator of tones 446 Various materials for general pur- poses 220 Varying magnitude of inclination 790 Vater, Model of steam cylinder with different slide valves 633 Velocity and quantity of outflow 350, 351, 353 - angular 290 - of flow 354, 355 - of ions' migration . . 944, 946 - of light 465, 491 - of sound 434 Ventilator model 282 Vernier-caliper 223 - model, circular .... 228, 229 - linear 221 Versed sine motion . .318 Page Vertical arrangement of sliding resistances 1073 — galvanometer 874, 875 — see dead beat universal instrument 902 — galvanoscopes 875 - rules 222, 223 Vessel for conductivity measuring 930 - for dialysis 365 - for light-absorbing liquids . 516 - for preserving ice blocks . 214 — of 1 cubic inch 230 Vestal sieve 380 Vibrating air columns .... 426 - bars 433—440 — strings, plates, bells .440 — 443 Vibrations analyzed 300 — and oscillations: see Strobo- scopic cylinder. . . . 283,417 Vibration curves 451 — 455 — harmonic 298, 299 - microscope 457, 458 — — see also tuning fork clock 463 — of an air column 433 — of liquid films 443 — of sounds 415, 417 - planes of the light .... 563 Vibrator after Weinhold . . .1041 Vibrographs 456 Vice, parallel see vol. I. View of factury V Views, stereoscopic 524 Violet glass plate 519 Violle, Actinometer 651 — Pair of bulbs 651 Viscosity test pieces 311 Vogel, Float apparatus .... 344 - Pocket spectroscope . . .511 see also Polarisation appa- ratus 554 - Spark tube (fulgurator) . . 514 - Star spectra table 518 Volkmann, Rope wave apparatus 414 Volta's Pair of plates 839 - Pile 840 Voltage coils, additional . . , 903 Voltaic cell ; 845 - electricity 839 — 949 Voltameters 940 — 943 Voltmeters 901 — 911 Volume gauges for oxygen flasks see vol. I. - measuring . . . 216, 217. 230 — of gases determined . . . 346 Volumnometer 380 Vowel apparatus 459, 460 V-shaped glass tube 944 W Walferdin, Metastatic thermo- meter 578 Wall bracket and wall arm . . 842 - for galvanometer . . . 883 — crane 331 v. Waltenhoien, Pendulum 952, 955, 956, 976 - Magnetic saturation .... 957 Walter's Picein Wanka, Top apparatus .... 293 Watch glasses 217 — glass clamps 217 Water air pump see vol. I. - for preliminary ex- hausting 399 - bath 210 - battery 809, 841 — behaviour on freezing or boil- ing 574 Page Water box for protecting the sele- nium cell 1059 — calorimeter 618 - chamber (optical eye) . . . 523 — circulation 573, 574 - decomposing apparatus 940—942 — dilatometer 572 — -drawing wheel, discharging 357, 358 - expansion, absolute .... 594 — freezing of 574 — gauge 658 — hammer 605, 606 — influence machine . . . .816 — jet blowers see vol. I. - is composed of drops. . 351 - projectile apparatus . . 264 - lead mouthpiece 354 — meters 354, 355 — motor 357 - pyrometer (Siemens') . . . 587 — screw, Archimedian .... 357 — siren 421 - tap 207 — thermometer 577 — trap for Weinhold's calori- meter 618 - trough for Paalzow optical bench 557 - vapour tension 602 — vapour, working action . .631 — vessels, communicating . . 814 — wheels 355, 356 Watt, Ball governor . . . 281, 637 — Low pressure engine . 634, 636 — Parallelogram 316 - Pendulum 281 — Planet wheels 324 — Regnault, Tension of water vapour 604 Wattmeter for demonstration . 905 Wave apparatus . . 411—417, XV - detectors (coherers) . 1051, 1052 — Hertzian 1039—1045 - length determining . . 544, 548 - spectrometer 506 - machines .... 411 — 417, XV — -meter 1044, 1045 — motions 411 — 417 - siren 423 — — disc 283, 420 — transmitter for Hertzian waves 1041 — trough 413 — tube 336 Waves, stationary. . . .1043, 1044 Wax cylinders for phonographs. 461 Waxed wire for house telegraph 961 Weather telegraph 654 Weber, Compass 793 - Free vibrating steam pipe. 429 — Light-angle-measurer . . . 465 — Magnetometer 794 — Photometer 469 — Trough for wave motions. . 413 - Unipolar induction . . . .976 Wedge 313 - apparatus 272 — compensator 556, 560 — friction wheels 327 - of gypsum 564 Wedges, of wood 206 Wedge-shape air plates .... 544 Wedgwood, Pyrometer .... 587 Wehnelt, Interrupter 982, 1010, XV - Oscillograph 900 — Valve tubes 1024 Starke, Electrolytic inter- rupter 928 Weighing machines, models . . 276 — pan for demonstration ba- lance . . . 240 See also the Subject-matter Index in vol. I. 1128 Alphabetical Name and Subject-matter Index. Page Weight bridge, Roberval's . . . 276 - dilatometer 571, 572 Weighted flask with gauze seal 339 Weights for balances . . .241 — 244 - for elasticity in bending apparatus 304 - with double hooks . . 260, 273 - with hooks 266, 441 Weight thermometer 572 Weiler, Demonstration aneroid barometer 375 - Double pachytrope .... 1003 - Tesla-motor 1003 - Three-phase current model 1003 Weinhold A., Air thermometer. 583 - Alternating and three-phase current machine 1000 - Alternating current reflecting galvanoscope 892 - Alternating current trans- former 1008 - Archimedian principle . . . 343 - Attraction of mass .... 300 - Behaviour of saturated and superheated steam .... 602 - Branly tube 1041 - Calorimeter 618 - Calorimeter for high tempera- tures 620 - Capillary galvanoscope . . 946 - Coil for showing induction by earth field 972 - Complete set for demonstrat- ing Hertz's experiments and wireless telegraphy. .1040 - Condenser 833 - Contact device for Foucault's pendulum 298 - Coulomb's law for electricity 804 - Cryophorous 608 - Cylindrical beaker with evac- uated quadruple walls . . 611 - Damping by induction . . 976 - Demonstration air thermo- meter 584 - Demonstration goniometer 479, 480 - Demonstration photometer 468 - Discharge electrometer . . 841 - Drawings for showing the blind spot 523 - Drum armature 991 - Electricity at the end of an elongated conductor . . . 806 - Electromagnet 952 - Fall cylinder 404 - Fall machine (Atwood's) . 253 - Foucault's pendulum . . . 298 - Freezing of water, melting of ice, boiling water 574 - Gas endosmose apparatus . 410 - Gas flame manometer 432, 433 - Gay-Lussac's law of the ex- pansion coefficient of gases 574 - Grating spectroscope for Zee- man-phenomenon .... 509 - Hertz' experiment . . . .1040 - Hertzian wave transmitter 1041 - Inclined plane 268 - Induction coils 974 - Influence machine .... 822 - Inverted float 380 - Laws of reflection .... 474 Linear expansion 569 - Lodge's resonance experi- ment 1035 - Longitudial wave machine . 411 Mercury distilling apparatus 399 - Microphone 1054 - Mirror galvanometer . .• .1013 Model of a three-phase motor 1000 — Model of balance beam . . 275 Page Weinhold, A., Model^of reflecting galvanometer 878 - Oil-insulated high tension transformer 1035 - Optical bench 472 - Optical bench for explaining microscope and telescopes. 531 - Paper tube electroscope . .801 - Peltier's thermoelectric ex- periment 1063 — Pendulum for the moment of inertia 290 - Pendulum laws 260 - Phalanges in glass tube . . 1073 — Piezometer 358 - Plateau's apparatus .... 360 — Polarising battery .... 853 - Porro prism combination . 503 - Precision work stand . . . 202 - Radiophone 649 — Reflecting galvanometer . . 877 - Refraction and reflection ap- paratus 484 — Resistance experiments . .911 - Retardation of freezing . . 608 — Reversal of sodium line . . 517 - Reversing pendulum . . . 295 - Rotation of liquid conduc- tors 971. - Set of Tesla apparatus . .1034 - Small steam boiler .... 569 - Speaking arc lamp .... 1058 - Stability apparatus .... 274 - Standard copper zinc cell . 844 - Stationary electric waves . 1043 — Steam-boiler 213 - Steam capsule .... 645, 647 — Steatite piece 797 - Syphon . 381 - Thermal conduction of gases 642 - Thermoscope 573, 588 — Thermoscope for radiant heat 643 - Tube level model 335 - Vacuum syphon . . . 360, 361 - Vernier model 221 - Vessel for dialysis 365 - Vibration microscope . . . 458 - Water decomposing appara- tus !>41 - Water jet projectile appa- ratus 264 - Wheatstone bridge .... 926 - Wireless telegraphy .... 1040 Weisbach, Outflow apparatus . 350 Weiss, Electromagnet . . . 956, 957 Well-springs 334, 351 Wernicke, Liquid prisms. . 502, 560 Wertheim, Tones of steel when magnetized 420, 957 Wesselhoft, Distributing appara- tus 805 Westien, Universal clamp . . . 202 Weston, Standard cell .... 845 Westphal, Single arm balance. . 236 Wheatstone Bridges . . . . 918, 919 - Bridge explained . . . 917, 918 - Bridge key 868 - Bridge on galvanometer . . s77 — Kaleidophone 451 - Mirror stereoscope .... 524 — Photometer 468 - Precision bridges . . . 924. !i2.~> — Rheostat 912 - Vibration curves . . .451 — 455 - Wave machine 4 Hi - -Kirchhoff bridge '.121. Wheel, Barlow's 969 — sector and small spur wheel 319, 320 suspension .'i2ll - with movable paddles . . 357 Page Whirl, electric 825 - for fitting on I he high tension transformer In:!:! Whirling apparatus 2S1 - tables 278, 27^, XV Whirlpool :!.->( Whistle, Galton's n;> Whistling arc lamp ld,">s White metal sheet plate . . . 812 — — slab r.'.Mi Wichert, Electrometer . . . .841 Wide burner attachment . . . 210 - tube and rupillary tube. . :i(>2 Wiedemann. Calorimeter .... tils - Calorimeter for liquids . . <>!!> - Electrolysis of salt solutions and migration of ions . . !U4 — Gas calorimeter 621 - Measuring the liquid carried over to the negative pole !)4.~> - Mercury filtration apparatus :i!i!) - Mirror galvanometer . . .SSI - Model geyser (>30 - Moving coil mirror galvano- meter 887 - Thermal conduction in rods 639 Wiedemann, G. Electric needle. 811 Wien, Standards of self-induction 976 Wild, Double plate 565 - Wind vane (i.">s Willemite 1027 Wimshurst, Influence machines 819—821, 1072 Wind chests 4 •_'.-,. 42(i - see also vol. I. - on lecture table, see vol. I. - Fan 405 , Winding gear 330 Windlass 313, 328—330 Windlass for yarns, see special list . Windmill of cardboard . 409, ."(i Window darkeners see vol. I. Wind pressure regulator . . . 42t> — vane . . lir.x - and wind wheel . . . 2s2 - wheel of paper 4 (14 Winding formers !>!M Wingen, Photometers . . . 46(>. KIT Winkelmann, Vacuum double bulb Winter, Ring for disc elect rie machines 816 Wire baskets and hollow sphere 801 - cage sos — coil .... 962, 965, 966. '.17 1 - fork, insulated 802 - frame on wood board . . . SHIS - gauge 223 - gauze cylinder 1140 — — globe film. .-,!I7 — grating -Vis - for Hertzian wave ex- periments lot 2 - net 210 - cylinder si 2 - tongs 59S netting, flexible 811 - spiral with ebonite handle, sns — triangles 2lo — waxed !•(>! Wires, conducting . '2(>C,. Sin. lli.->4 — of constantan, German sil- ver etc '•" 1 — of copper . . . -'or,. •_'<>:. !tll Wireless telegraphy Into. HMIi -lo.-,3 - telephony lo,">7 Wislicenus, I'ranotrope ... Withdrawable condenser . . Wittmann, Oscillograph .... '.too Wolf, Safety lamp 640 Wollaston, Camera lucida . . . ">30 — (VII . .... 847 See also the Subject-matter Index in vol. I. Alphabetical Name and Subject-matter Index. 1129 WollastOn, t'l.yonliorous . Ilypsomeler .... Pi-ism '4 goniometer Wolpert. Air tester Page. (HIS 662 509 4S1 856 Woltman, Mill :!.v> '•Vater mi'ter 355 Wommelsdorf, Influence machine S22 Wood liars, which sound . . . 4.'jl! blocks, parallclepipedic . . 2O(i - cone with brass tube . . . lili'.l - with pins 284 cylinder with paper .surface ~l',i frame, hook and wire for melt- linl - stretched with cardboard m>2 - with ring loud models of crystals .... Iniis prism wit h Huygheuian cons- truct ions 563 - protract .or 229 pyramid with brass tube . liHil - rod 2«iit scales with T-.-haped cross- section 894 - slabs, cut with and aciu-.- the grain 596 stand for measuring instru- ments 908 - for I'uliij's apparatus . 286 for vacinini tube . . . 1023 supports 206 wedges . ... . 206 Wood's Metal 601 Wood, Phase reversing plate . 549 Wooll, Slide valve cylinder . . 632 Page Work and heat 626—637, 591, 597 - bench sec vol. I. Working of the telephone . . . 1054 Work rail 252 Workshop equipment see vol. I. Work stand, physical . . . 201, 202 Worm, and wheel 323 -earing .... 313, 323, 324 Woulff's Flasks 219 Wright, Gypsum and mica com- bination 565 W -shaped decomposition cell . 944 Wunder, Thermocouple .... 1064 X X-ray equipments for medical use -ee special list. - induction coils . . . .978 — 981 X-ray negatives 1074 X-ray tubes 985 - tubes for evacuation by one's self 1016 school experiments . 1(573, 1074 Yaru-assorters see special list. - for connecting apparatus 803 Yarn-\viridlcs see special list. Young, Modulus 308 Zahlbruckner, Declination and in- clination 7S!I - Liquid's pressure 340 - Monocliord 441 Zamboni, Pile . . . 809, 810, S4o - Pile with protecting neck .10211 Zeeman-Kttect 507, .",o'.i Zehnder, Battery of accumulators 856 discharge tube 1043 - Primary and secondary con- ductor 1042, 1043 Zeiss, < (ptical apparatus for string galvanometer 892 -Telescopes 543 Zenith prism for telescopes . . 543 Zickler, Tube 1053 Zinc condensor plate 803 - -copper cell 845, 847 - disc, amalgamated .... 1026 - plate 839 - amalgamated 813 for wire coil . . . 962, 967 - plate, spare 852 sulphide screen 1027 Zirconium plate 617 Zollner, Double radiometer . . 1021 Zwick, Lens apparatus .... 496 - Myopia and presbyopia . . 523 - Optical apparatus .... 496 — Voltameter . 941 The pages 1201 — 1240 are bound in voL I. r \ RETURN 1 5 1969 6 REC'D LD OqC 1 ' I76B . General Library ,versKyo,Cali£r Berkeley GENERAL LIBRARY - U.C. BERKELEY